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Prior research has shown that urine of women with preeclampsia (PE) contains amyloid-like aggregates that are congophilic (exhibit affinity for the amyloidophilic dye Congo red) and immunoreactive with A11, a polyclonal serum against prefibrillar β-amyloid oligomers, thereby supporting pathogenic similarity between PE and protein conformational disorders such as Alzheimer's and prion disease. The objective of this study was to interrogate PE urine using monoclonal antibodies with previously characterized A11-like epitopes. Over 100 conformation-dependent monoclonals were screened and three (mA11-09, mA11-89, and mA11-205) selected for further confirmation in 196 urine samples grouped as follows: severe features PE (sPE, n = 114), PE without severe features (mPE, n = 30), chronic hypertension (crHTN, n = 14) and normotensive pregnant control (P-CRL, n = 38). We showed that the selected conformation-specific monoclonals distinguished among patients with varying severities of PE from P-CRL and patients with crHTN. By use of latent class analysis (LCA) we identified three classes of subjects: Class 1 (n = 94) comprised patients whose urine was both congophilic and reactive with the monoclonals. These women were more likely diagnosed with early-onset sPE and had severe hypertension and proteinuria; Class 2 patients (n = 55) were negative for congophilia and against the antibodies. These were predominantly P-CRL and crHTN patients. Lastly, Class 3 patients (n = 48) were positive for urine congophilia, albeit at lower intensity, but negative for monoclonal immunoreactivities. These women were diagnosed primarily as mPE or late-onset sPE. Collectively, our study validates conformation-dependent Aβ imunoreactivity of PE urine which in conjunction to urine congophilia may represent an additional indicator of disease severity., (Copyright © 2022 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.)

Objective: Accurate and timely diagnosis of anemia in pregnancy is necessary for safe management of abortion care. Screening for anemia in abortion care is often accomplished using commercially-available point-of-care tests from capillary blood, but the validity of this test has not been investigated in the context of abortion care. We sought to determine the accuracy of a capillary hemoglobin (Hb) among pregnant patients seeking induced abortion., Study Design: We conducted a retrospective study of patients seeking abortion care at the University of Illinois at Chicago. We identified 108 subjects with paired capillary Hb and venous complete blood count (CBC) hemoglobin measurements within 7 days of each other and within 14 days before abortion. Agreement analysis was performed using Passing-Bablok regression and Bland-Altman plots., Results: More patients were deemed anemic by capillary than by venous Hb measurement (32% vs 19%, p = 0.030). Capillary Hb correlated with venous Hb (r = 0.85, p < 0.001). The average bias for capillary Hb was -1.1 ± 1.0 g/dL. Step-wise, multivariable linear regression identified venous Hb as the only determinant of capillary Hb, and failed to identify any other predictors of bias. The agreement analysis between capillary and venous Hb by Passing-Bablok regression demonstrated systematic and proportional differences., Conclusion: Results from capillary Hb may be biased toward diagnosing anemia and should be interpreted with caution., Implications: Misdiagnosing anemia in abortion care can have several consequences and may prevent timely medical abortion or cause delayed procedural abortion. Clinical correlation, and possibly confirmation by venous complete blood count measurement, should be considered before clinical decision-making based solely upon the capillary point-of-care assay., (Copyright © 2021 Elsevier Inc. All rights reserved.)

We conducted a protein-protein interaction (PPI) network study searching for proteins relevant to pregnancy-associated COVID-19 in pregnancy complicated with severe preeclampsia (sPE) and intra-amniotic infection and/or inflammation (Triple-I). PPI networks from sPE and Triple-I were intersected with the PPI network from coronavirus infection. Common proteins included the SARS-CoV-2 entry receptor ACE2 and ENDOU, a placental endoribonuclease homologous to Nsp15, a protein produced by the virus to escape host immunity. Remarkably, placental ENDOU mRNA expression far exceeded that of ACE2. Immunohistochemistry confirmed ENDOU localization at the hemochorial maternal-fetal interface. Investigation of ENDOU's relevance to vertical transmission of SARS-CoV-2 is further warranted., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

α 2 -Adrenergic receptors (α 2 ARs) are G-protein-coupled receptors involved in catecholamine signaling by extracellular regulated protein kinase 1 and 2 (ERK1/2) pathways. We examined placental expression and function of α 2 AR subtypes in women with severe preeclampsia (sPE) with and without intrauterine growth restriction (IUGR). Placental biopsies were analyzed from 52 women with i) sPE (n = 8); ii) sPE + IUGR (n = 9); iii) idiopathic IUGR (n = 8); iv) idiopathic preterm birth (n = 16); and v) healthy term controls (n = 11). Expression of α 2 AR subtypes (α 2A , α 2B , α 2C ) and phospho-ERK1/2 (receptor activation marker) was investigated by immunohistochemistry and/or quantitative real-time RT-PCR. The effects of α 2C AR knockdown on syncytialization (syncytin-1 and -2) and β-human chorionic gonadotropin secretion were examined in BeWo cells stimulated with forskolin. The effects of α 2 AR agonist UK 14,304 and specific α 2C AR antagonist were tested, using a trophoblast migration assay. All three α 2 ARs were expressed and functionally active in human placenta with site-specific localization. Highest α 2B AR and α 2C AR mRNA expression was identified in sPE + IUGR. α 2C AR knockdown increased expression of syncytin-1 and -2 but decreased secretion of β-human chorionic gonadotropin. UK 14,304 impaired trophoblast migration. The observed α 2 AR expression pattern suggests different function for each subtype. α 2C AR modulates trophoblast syncytialization and migration and may carry pathogenic role in sPE + IUGR., (Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Objective: Haptoglobin (Hp) has key immunoregulatory roles that vary with phenotype (Hp1-1, Hp2-1, Hp2-2). Cord blood Hp expression is switched-off in the normal fetus. We hypothesized that in the setting of fetal inflammation placenta becomes inundated with Hp of fetal origin that in turn modulates the output of PGE 2 and MMP-9 in a phenotype dependent manner., Methods: Placentas from 40 pregnancies complicated by preterm birth (PTB) (<37 weeks), without (n = 15) or with (n = 25) intra-amniotic infection and histological chorioamnionitis (HCA) were scored for intensity of Hp immunostaining. Hp mRNA levels were evaluated by PCR. Cord blood Hp levels, switch-on status and phenotypes were determined by ELISA and Western blotting. Using a villous trophoblast explant system we investigated if Hp can modulate the release of PGE 2 and MMP-9 in the presence or absence of lipopolysaccharide (LPS)., Results: All cases with HCA had positive Hp immunoreactivity within fetal vascular spaces. Hp staining intensity correlated with cord blood Hp levels and IL-6. Placentas with and without HCA had similar Hp mRNA levels suggesting Hp immunostaining in the fetal spaces is of fetal rather than placental origin. Both Hp1-1 and Hp2-2 up-regulated PGE 2 release in the presence of LPS (2-fold over the LPS level, P < .05), without affecting MMP-9 concentrations., Conclusions: Fetal Hp switch-on status, a marker of antenatal exposure to intra-amniotic infection/inflammation, can be reliably established through evaluation of archived placental specimens. In the setting of infection/inflammation, Hp enhances placental PGE 2 output thereby supporting the role of the fetus in triggering parturition., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: We performed RNA sequencing with the primary goal of discovering key placental villous trophoblast (VT) and decidua basalis (DB) transcripts differentially expressed in intra-amniotic infection (IAI)-induced preterm birth (PTB)., Methods: RNA was extracted from 15 paired VT and DB specimens delivered of women with: 1) spontaneous PTB in the setting of amniocentesis-proven IAI and histological chorioamnionitis (n = 5); 2) spontaneous idiopathic PTB (iPTB, n = 5); and 3) physiologic term pregnancy (n = 5). RNA sequencing was performed using the Illumina HiSeq 2500 platform, and a spectrum of computational tools was used for gene prioritization and pathway analyses., Results: In the VT specimens, 128 unique long transcripts and 7 mature microRNAs differed significantly between pregnancies complicated by IAI relative to iPTB (FDR<0.1). The up-regulated transcripts included many characteristic of myeloblast-derived cells, and bioinformatic analyses revealed enrichment for multiple pathways associated with acute inflammation. In an expanded cohort including additional IAI and iPTB specimens, the expression of three proteins (cathepsin S, lysozyme, and hexokinase 3) and two microRNAs (miR-133a and miR-223) was validated using immunohistochemistry and quantitative PCR, respectively. In the DB specimens, only 11 long transcripts and no microRNAs differed significantly between IAI cases and iPTB controls (FDR<0.1). Comparison of the VT and DB specimens in each clinical scenario revealed signatures distinguishing these placental regions., Discussion: IAI is associated with a transcriptional signature consistent with acute inflammation in the villous trophoblast. The present findings illuminate novel signaling pathways involved in IAI, and suggest putative therapeutic targets and potential biomarkers associated with this condition., (Copyright © 2016. Published by Elsevier Ltd.)

Introduction: A major issue in the transcriptomic study of spontaneous preterm birth (sPTB) in humans is the inability to collect healthy control tissue at the same gestational age (GA) to compare with pathologic preterm tissue. Thus, gene expression differences identified after the standard comparison of sPTB and term tissues necessarily reflect differences in both sPTB pathology and GA. One potential solution is to use GA-matched controls from a closely related species to tease apart genes that are dysregulated during sPTB from genes that are expressed differently as a result of GA effects., Methods: To disentangle genes whose expression levels are associated with sPTB pathology from those linked to GA, we compared RNA sequencing data from human preterm placentas, human term placentas, and rhesus macaque placentas at 80% completed gestation (serving as healthy non-human primate GA-matched controls). We first compared sPTB and term human placental transcriptomes to identify significantly differentially expressed genes. We then overlaid the results of the comparison between human sPTB and macaque placental transcriptomes to identify sPTB-specific candidates. Finally, we overlaid the results of the comparison between human term and macaque placental transcriptomes to identify GA-specific candidates., Results: Examination of relative expression for all human genes with macaque orthologs identified 267 candidate genes that were significantly differentially expressed between preterm and term human placentas. 29 genes were identified as sPTB-specific candidates and 37 as GA-specific candidates. Altogether, the 267 differentially expressed genes were significantly enriched for a variety of developmental, metabolic, reproductive, immune, and inflammatory functions. Although there were no notable differences between the functions of the 29 sPTB-specific and 37 GA-specific candidate genes, many of these candidates have been previously shown to be dysregulated in diverse pregnancy-associated pathologies., Discussion: By comparing human sPTB and term transcriptomes with GA-matched control transcriptomes from a closely related species, this study disentangled the confounding effects of sPTB pathology and GA, leading to the identification of 29 promising sPTB-specific candidate genes and 37 genes potentially related to GA effects. The apparent similarity in functions of the sPTB and GA candidates may suggest that the effects of sPTB and GA do not correspond to biologically distinct processes. Alternatively, it may reflect the poor state of knowledge of the transcriptional landscape underlying placental development and disease., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Proteomics, a relatively young science, originally emerged as a complement to genomics research. By definition, the goal of proteomics is to provide a snapshot of all the proteins within an organism, tissue or biological sample at a given moment. Proteomics has the ability to single out one or more proteins (biomarkers) that change consistently in affected subjects as compared to those disease-free. From a proteomics perspective, chorioamnionitis poses both challenges and opportunities. Challenges relate to the dynamic course of the inflammatory process, and compartmentalization of the gestational sac in relation to the maternal compartment. An inability to evaluate the amniotic fluid non-invasively and repeatedly for meaningful changes in its proteome, and lack of a true gold standard for diagnosis of inflammation and/or infection, represent additional challenges. On the other hand, the unbiased and holistic nature of proteomics offers a real opportunity to improve the current diagnostic and prognostic algorithms for chorioamnionitis. Even at this current stage there are reasons to believe that proteomic biomarkers will improve the understanding of how chorioamnionitis programs or affects the fetus in utero, thus defining its exposome (sum of interactions between genetic make-up of the fetus and the intrauterine environment) of pregnancies affected by infection and/or inflammation. This review summarizes the results of proteomics studies that have aimed or reached these goals., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: We sought to characterize serum angiogenic factor profile of women with complete placenta previa and determine if invasive trophoblast differentiation characteristic of accreta, increta, or percreta shares features of epithelial-to-mesenchymal transition., Study Design: We analyzed gestational age-matched serum samples from 90 pregnant women with either complete placenta previa (n = 45) or uncomplicated pregnancies (n = 45). Vascular endothelial growth factor (VEGF), placental growth factor, and soluble form of fms-like-tyrosine-kinase-1 were immunoassayed. VEGF and phosphotyrosine immunoreactivity was surveyed in histological specimens relative to expression of vimentin and cytokeratin-7., Results: Women with previa and invasive placentation (accreta, n = 5; increta, n = 6; percreta, n = 2) had lower systemic VEGF (invasive previa: median 0.8 [0.02-3.4] vs control 6.5 [2.7-10.5] pg/mL, P = .02). VEGF and phosphotyrosine immunostaining predominated in the invasive extravillous trophoblasts that coexpressed vimentin and cytokeratin-7, an epithelial-to-mesenchymal transition feature and tumorlike cell phenotype., Conclusion: Lower systemic free VEGF and a switch of the interstitial extravillous trophoblasts to a metastable cell phenotype characterize placenta previa with excessive myometrial invasion., (Published by Mosby, Inc.)

Objective: The objective of the study was to test whether ultrasound-measured fetal adrenal gland volume (AGV) and fetal zone enlargement (FZE) predicts preterm birth (PTB) better than cervical length (CL)., Study Design: Three-dimensional and 2-dimensional ultrasound were used prospectively to measure fetal AGV, FZE, and CL in women with preterm labor symptoms. We corrected AGV for fetal weight (cAGV). The ratio between whole gland depth (D) and central fetal zone depth (d) (d/D) was used to measure FZE. Ability of cAGV, d/D, and CL to predict PTB 7 days or less was compared., Results: Twenty-seven of 74 women (36.5%) presenting between 21 and 34 weeks had PTB of 7 days or less. FZE greater than 49.5% was the single best predictor for PTB (sensitivity/specificity 100%/89%) compared with cAGV (81%/87%) and CL (56%/60%; P < .05). Prediction was independent of obstetrics history and tocolytic use., Conclusion: The 2-dimensional measurement of the adrenal gland FZE is highly effective performing superior to CL in identifying women at risk for PTB within 7 days., (Published by Mosby, Inc.)

There is little known about healing of the uterus after Cesarean delivery (CD). Uterine wound repair was studied by using two strains of mice with different wound healing characteristics: MRL/MpJ(+/+) (MRL: "high-healer" phenotype) and C57Bl/6 ("low-healer" phenotype). First, we examined the morphology and histology of the uterine wall repair. We identified wound granulation tissue 3 days post-CD in both strains, albeit less in the MRL strain. Macroscopically, no scar could be identified either in MRL or C57Bl/6 mice on day 60 post-CD. However, histologically, we found significant differences in wound integration, inflammation, and collagen birefringence between the two strains of mice. Using a histological index, we provided evidence for significant differences in mitotic activity in the initial phases of uterine healing among strains. Functional behavior of the uterine scar also was analyzed by using biomechanical parameters such as slope (measure of stiffness), yield point (measure of elasticity), and break point (measure of strength). There were significant differences in stiffness of the scarred myometrium between the two phenotypes. MRL mice displayed a significantly lower yield point compared with C57Bl/6. The break point was reached faster on days 15 and 60 in both C57Bl/6 and MRL strains compared with day 3 post-CD. Our findings indicate that differences in regenerative ability translate in histological, mitotic, and functional differences in biomechanical properties of the scarred myometrium after CD.

Objective: Distinct processes govern transition from quiescence to activation during term (TL) and preterm labor (PTL). We sought gene sets that are responsible for TL and PTL, along with the effector genes that are necessary for labor independent of gestation and underlying trigger., Study Design: Expression was analyzed in term and preterm with or without labor (n=6 subjects/group). Gene sets were generated with logic operations., Results: Thirty-four genes were expressed similarly in PTL/TL but were absent from nonlabor samples (effector set); 49 genes were specific to PTL (preterm initiator set), and 174 genes were specific to TL (term initiator set). The gene ontogeny processes that comprise term initiator and effector sets were diverse, although inflammation was represented in 4 of the top 10; inflammation dominated the preterm initiator set., Conclusion: TL and PTL differ dramatically in initiator profiles. Although inflammation is part of the term initiator and the effector sets, it is an overwhelming part of PTL that is associated with intraamniotic inflammation., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Immune activation represents an adaptive reaction triggered by both noxious exogenous (microbes) and endogenous [high mobility group box-1 protein (HMGB1), S100 calcium binding proteins] inducers of inflammation. Cell stress or necrosis lead the release of HMGB1 and S100 proteins in the extracellular compartment where they act as damage-associated molecular pattern molecules (or alarmins) by engaging the receptor for advanced glycation end-products (RAGE). Although the biology of RAGE is dictated by the accumulation of damage-associated molecular pattern molecules at sites of tissue injury, the role of RAGE in mediating antenatal fetal injury remains unknown. First, we studied the relationships at birth between the intensity of human fetal inflammation and sRAGE (an endogenous RAGE antagonist), HMGB1, and S100beta protein. We found significantly lower sRAGE in human fetuses that mounted robust inflammatory responses. HMGB1 levels correlated significantly with levels of interleukin-6 and S100beta in fetal circulation. We then evaluated the levels and areas of tissue expression of RAGE, HMGB1, and S100beta in specific organs of mouse fetuses on E16. Using an animal model of endotoxin-induced fetal damage and preterm birth, we determined that inflammation induces a significant change in expression of RAGE and HMGB1, but not S100beta, at sites of tissue damage. Our findings indicate that RAGE and HMGB1 may be important mediators of cellular injury in fetuses delivered in the setting of inflammation-induced preterm birth.

Objective: We hypothesized that the genetic makeup has an impact on the functional behavior of the uterine cervix. Therefore, we compared the biomechanical properties of uterine cervix in postpartum in 2 strains of mice that differ in their underlying regenerative collagen remodeling characteristics: MRL/MpJ+/+ (MRL: high regenerative repair) and C57BL/6 (C57: low regenerative high fibrotic repair)., Study Design: Cervical tensile proprieties were assessed on day 3, 15, and 60 postpartum in MRL (n = 14) and C57 (n = 13) mice (4-5 animals at each time point). Stress-strain curves were generated using Shimadzu EZ-test instrumentation. Cervical tissue was stretched by 0.42 mm/min until rupture. Parameters of viscoelasticity including slope (a measure of stiffness), yield point (YP; moment when tissue changes its proprieties from elastic to plastic), and break point (BP; measure of tissue strength) were recorded and analyzed blindly between strains. Data were normalized to the weight of the tissue and analyzed by 2-way analysis of variance. Histological and collagen birefringence evaluation of the uterine cervix (MRL: n = 4; C57: n = 4) was performed 5 days after delivery., Results: At 3 and 15 days postpartum, cervices of MRL mice were significantly more compliant than those of C57 (P < .001). MRL mice displayed a significant increase in stiffness from day 3 to day 60 (slope, median +/- SEM: day 3: 3.1 +/- 0.5 vs day 15: 20.3 +/- 4.9 vs day 60: 33.1 +/- 3.5 N/mm per gram; P < .001). In contrast, the stiffness of C57 cervices reached maximum on day 15 (slope day 3: 14.1 +/- 4.3 vs day 15: 40.0 +/- 6.5 N/mm per gram; P = .02) and rested at a similar level on day 60 (day 60: 26.1 +/- 7.0 N/mm per gram; day 60 vs day 15: P = .937). More force was required to reach YP in C57 on day 3 (C57: 72.5 +/- 14.7 vs MRL: 19.9 +/- 1.6 N/g; P < .001) but not on either day 15 (C57: 156.1 +/- 27.5 vs MRL: 109.2 +/- 26.0 N/g; P = .120) or on day 60 (C57: 143.4 +/- 26.5 vs MRL: 164.5 +/- 18.7 N/g; P = .412). There was a significant decrease in BP in both strains on both day 15 and day 60 compared with day 3 postpartum (P = .856 for strain, P = .008 for day). MRL mice displayed significantly less cervical collagen birefringence compared with C57 control (P < .001) but increased proteoglycan staining and increased water content., Conclusion: We provide evidence that genetic makeup may have an impact on cervical tissue remodeling and function. There are significant differences in postpartum cervical stiffness and compliance that vary with the regenerative collagen remodeling phenotype.

Objective: The objective of the study was to evaluate the fetal renal artery impedance in the context of inflammation-associated preterm birth., Study Design: We conducted a prospective Doppler assessment of the fetal renal artery impedance in 70 singleton fetuses. The study group consisted of 56 premature fetuses (median, 28.1 [interquartile range, 25.3-30.6] weeks at enrollment). Gestational age (GA) reference ranges were generated based on fetuses with uncomplicated pregnancies (n = 14). Doppler studies included renal artery pulsatility index (PI), resistance index (RI), systolic/diastolic (S/D) ratio, and presence or absence of end-diastolic blood flow. Proteomic profiling (surface-enhanced laser desorption ionization time-of-flight) was used for assessment of intraamniotic inflammation and biomarker peak corresponding to beta2-microglubin. Data were interpreted in relationship to amniotic fluid index (AFI), cord blood interleukin (IL)-6 and erythropoietin (EPO) levels. The cardiovascular and metabolic profiles of the neonates were investigated in the first 24 hours of life., Results: Fetuses delivered by mothers with intraamniotic inflammation had higher cord blood IL-6 but not EPO levels. Fetal inflammation did not affect either renal artery PI, RI, S/D ratio, or end-diastolic blood flow. Neonates delivered in the context of intraamniotic inflammation had higher serum blood urea nitrogen levels, which correlated significantly with AF IL-6 levels. The renal artery RI and SD ratio were inversely correlated with the AFI independent of GA, cord blood IL-6, and status of the membranes., Conclusion: The fetus is capable of sustaining normal renal artery impedance despite inflammation. Resistance in the renal vascular bed affects urine output independent of inflammation.

Objective: The cause of preeclampsia remains unknown and the diagnosis can be uncertain. We used proteomic-based analysis of urine to improve disease classification and extend the pathophysiologic understanding of preeclampsia., Study Design: Urine samples from 284 women were analyzed by surface-enhanced laser desorption/ionization. In the exploratory phase, 59 samples were used to extract the proteomic fingerprint characteristic of severe preeclampsia requiring mandated delivery and to develop a diagnostic algorithm. In the challenge phase, we sought to prospectively validate the algorithm in 225 women screened for a variety of high- and low-risk conditions, including preeclampsia. Of these, 19 women were followed longitudinally throughout pregnancy. The presence of biomarkers was interpreted relative to clinical classification, need for delivery, and other urine laboratory measures (ratios of protein to creatinine and soluble fms-like tyrosine kinase-1 to placental growth factor). In the translational phase, biomarker identification by tandem mass spectrometry and validation experiments in urine, serum, and placenta were used to identify, quantify, and localize the biomarkers or related proteins., Results: We report that women with preeclampsia appear to present a unique urine proteomic fingerprint that predicts preeclampsia in need of mandated delivery with highest accuracy. This characteristic proteomic profile also has the ability to distinguish preeclampsia from other hypertensive or proteinuric disorders in pregnancy. Pregnant women followed longitudinally who developed preeclampsia displayed abnormal urinary profiles more than 10 weeks before clinical manifestation. Tandem mass spectrometry and de novo sequencing identified the biomarkers as nonrandom cleavage products of SERPINA1 and albumin. Of these, the 21 amino acid C-terminus fragment of SERPINA1 was highly associated with severe forms of preeclampsia requiring early delivery. In preeclampsia, increased and aberrant SERPINA1 immunoreactivity was found in urine, serum, and placenta, in which it localized predominantly to placental villi and placental vascular spaces adherent to the endothelium. In addition, significant perivascular deposits of misfolded SERPINA1 aggregates were exclusively identified in preeclamptic placentae., Conclusion: Proteomics-based characterization of urine in preeclampsia identified a proteomic fingerprint composed of SERPINA1 and albumin fragments, which can accurately diagnose preeclampsia and shows promise to discriminate it from other hypertensive proteinuric diseases. These findings provide insight into a novel pathophysiological mechanism of preeclampsia related to SERPINA1 misfolding, which may offer new therapeutic opportunities in the future.

Objective: The objective of the study was to evaluate longitudinally the in vivo changes in myometrial thickness (MT) during gestation in patients carrying twin gestations in relation to pregnancy outcome., Study Design: Serial abdominal ultrasounds were performed prospectively in 92 patients carrying twin gestations through each trimester. Ninety-seven patients pregnant with singletons served as controls. For twins, the primary endpoint was spontaneous delivery at less than 35 weeks' gestational age (GA). The myometrium was defined sonographically as the echohomogeneous layer between the serosa and the decidua and was measured at the anterior, fundal, and lower uterine segment (LUS) walls. The estimated fetal weight, maximum vertical pocket of amniotic fluid, and placental thickness were also assessed ultrasonographically at the same time as the MT and served as estimates for the contribution of each to the uterine volume. In twins, cervical length measurements were performed transvaginally, as clinically indicated. Data analysis included 2-way analysis of variance and linear, nonlinear, and multivariate regression., Results: A total of 41.3% of twin pregnancies (38 of 92) delivered preterm (< 35 weeks). There were no significant changes in measurements at the anterior and fundal site over time throughout pregnancy and no differences in these sites between twin and singleton gestations. Conversely, in both twins and singletons, there was a significant and gradual thinning of the LUS myometrium during gestation. In the absence of uterine contractions or symptoms of preterm labor, twins that delivered preterm had a significantly thinner LUS at an earlier gestation, compared with twins that delivered at term (P < .001), suggesting that LUS thinning occurred earlier in these cases. There was a significant correlation between cervical length and LUS thinning during gestation in twins that delivered 35 weeks GA or later (r = 0.352; P < .001) but not in those that delivered preterm (< 35 weeks GA; r = 0.125; P = .326)., Conclusion: Twin pregnancy is characterized by a significant, selective, and gradual thinning of the LUS during gestation, which does not occur in the anterior and fundal myometrium. Thinning of the LUS occurs earlier in twin pregnancies destined to deliver preterm. These observations suggest that similar to the cervix, the LUS changes dynamically during twin pregnancy and that this too may be assessed through ultrasound imaging.

Objective: The objective of the study was to test the hypothesis that inflammation modulates fetal erythroblastosis and/or the release of nucleated red blood cells (NRBCs) independent of hypoxia or fetal stress. We sought to determine whether fetal inflammation is associated with an elevation in neonatal NRBC count in the setting of inflammation-associated preterm birth., Study Design: The relationships between peripheral NRBC count, histological chorioamnionitis, umbilical cord interleukin (IL)-6, erythropoietin (EPO), cortisol, and acid-base status were analyzed in 68 preterm singletons, born to mothers who had an amniocentesis to rule out infection. Proteomic profiling of amniotic fluid identified presence of intraamniotic inflammation according to established parameters. NRBC counts were assessed within 1 hour of birth. Early-onset neonatal sepsis (EONS) was established based on hematological and microbiological indices. IL-6, EPO, and cortisol levels were measured by immunoassays. Fetal acid-base status was determined within 10 minutes of delivery. Parametric or nonparametric statistics were used., Results: Fetuses with EONS (n = 19) were delivered at earlier gestational ages (mean +/- SD: 27.1 +/- 2.8 weeks, P = .001) and more often by mothers with intraamniotic inflammation (P = .022) and histological chorioamnionitis (P < .001). Neonates with EONS had higher absolute NRBC counts (P = .011). NRBC counts were directly correlated with cord blood IL-6 levels (P < .001) but not with EPO, cortisol or parameters of acid-base status levels regardless of EONS status. These relationships remained following correction for gestational age, diabetes, intrauterine growth restriction, and steroid exposure., Conclusion: In the setting of inflammation-associated preterm birth and in the absence of hypoxia, elevations in NRBCs in the early neonatal period may be a direct response of exposure to inflammatory mediators in utero.

Objective: It has been shown that hypoxia leads to alterations in maternal serum levels of vascular endothelial growth factor (VEGF). In this study, we sought to test the hypothesis that chronic hypoxia increases maternal serum levels of VEGF, which in turn cause measurable changes in the viscoelastic properties of the rat uterine cervix., Study Design: Timed-pregnant adult Sprague-Dawley rats were exposed to hypoxia beginning on day 17 of gestation (term = day 22). The following groups of animals were studied: (1) nonpregnant controls (NP, n = 6); (2) normoxia 21% fraction of inspired oxygen (FiO2) (NMX, n = 6); and (3) severe hypoxia 10% FiO2 (HPX; n = 5). A hypoxic chamber was used to assure consistent hypoxic environment. Animals were killed on day 21 of gestation (before labor). Maternal blood was collected immediately following anesthesia and prior to euthanasia. Free serum levels of VEGF were measured by highly specific immunoassays. Tensile strength properties of the cervix were assessed using a stretching regimen designed to mimic labor. Physical parameters measured were: indicators of viscoelasticity (slope; measure of stiffness), plasticity (yield point [YP]; moment the tissue changes its properties from elastic to plastic), strength (break point [BP]; moment of tissue disruption), and displacement at YP (marks the duration of the viscoelastic phase of the stretching) and BP (a measure of the strength of the material). Data were normalized to the dry weight of the cervix., Results: Hypoxia is associated with increased serum levels of VEGF compared to NP or NMX groups (P = .001). Cervical stiffness was lower in NMX, compared with NP animals (P = .004), and was not significantly influenced by hypoxia (P > .05). Overall there was a significant inverse correlation between slope and maternal serum levels of VEGF (r = -0.85, P < .001). The force required to reach YP was significantly higher for the NP, compared with NMX and HPX groups (P = .004). Hypoxia did not alter the force required to reach the YP (NMX vs HPX, P > .05). Conversely, hypoxia significantly decreased the displacement at YP, indicating a shortening of the elastic phase (NMX vs HPX, P = .021). There was a significant inverse correlation between maternal serum levels of VEGF and the displacement at YP (r = -0.68, P = .002). In vivo, hypoxia decreased the force required to reached the BP (NMX vs HPX, P = .025), but there was no correlation between the levels of maternal serum VEGF and this indicator (r = -0.35, P = .170)., Conclusion: Chronic hypoxia induces measurable changes in maternal serum levels of VEGF and tensile properties of the rat cervix, specifically a shortening of the elastic phase. Hypoxia decreases the cervical strength to stretch and predisposes to rupture, but this effect seems to be unrelated to maternal serum levels of VEGF.

Objective: Nucleated red blood cells (NRBCs) in fetal circulation have been proposed as a marker of chronic hypoxia in fetuses with intrauterine growth restriction (IUGR). We sought to determine the effects of chronic hypoxia, chronic nitric oxide inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME), or both on NRBC counts, erythropoietin levels, and pathologic changes in an animal model of IUGR., Study Design: We assigned timed pregnant adult Sprague Dawley rats to the following groups: (1) 21% oxygen + saline solution (n = 7); (2) 21% oxygen + L-NAME (n = 8); (3) 10% oxygen + saline solution (n = 6); and (4) 10% oxygen + L-NAME (n = 6). We inserted osmotic pumps that were prefilled with saline solution or L-NAME subcutaneously on day 17 of gestation. The animals were placed in a Plexiglas hypoxic chamber, which ensured a constant hypoxic environment. The animals were killed on day 21 of gestation before the onset of spontaneous labor. We collected maternal and fetal blood for measurement of NRBC and erythropoietin levels. The results were interpreted in relationship to maternal arterial blood gases and hemoglobin and hematocrit levels. Fetuses were examined for gross abnormalities and histological abnormalities that are characteristic of vascular disruptions by a blind examiner to experimental manipulation., Results: Nitric oxide inhibition induced IUGR with maximal effect when both L-NAME and hypoxia treatments were combined. Inhibition of nitric oxide synthesis, but not chronic hypoxia, increased the number of fetal NRBCs and generalized hemorrhagic diathesis in utero. These features were aggravated significantly when the treatments were combined. Moreover, chronic hypoxia induced significant maternal metabolic acidosis and increased hematocrit and erythropoietin levels in maternal and fetal blood. Nitric oxide inhibition increased maternal hematocrit levels while decreasing maternal erythropoietin levels without significantly altering the maternal acid-base status. In contrast with chronic hypoxia, nitric oxide inhibition increased fetal NRBCs without affecting erythropoietin levels., Conclusion: Our findings indicate that the number of NRBCs in fetal circulation does not serve as a specific marker of chronic hypoxia that accompanies IUGR or of elevated erythropoietin levels but are an epiphenomenon that is related to the inhibition of nitric oxide.

Objective: Labor is associated with 'decidual activation' with increased proteolysis and extracellular matrix degradation. The balance between plasminogen activator inhibitor-1 (PAI-1) and urokinase (uPA) and tissue-type plasminogen activator (tPA) is an important determinant of proteolytic activity at the maternal-fetal interface. Thrombin released at the time of placental abruption (decidual hemorrhage) is known to promote decidual proteolysis and uterine contractions. This study investigates the separate and interactive effects of steroid hormones and thrombin on PAI-1, uPA, and tPA expression by term decidual cells (DCs)., Study Design: Term DCs were isolated by enzymatic digestion, purified, and depleted of leukocytes. Cells were treated with estradiol (10(-8) mol [E2]), medroxyprogesterone acetate (10(-7) mol [MPA]), both, or vehicle for 7 days. After 24-hour incubation with or without thrombin (0.1-2.5 U/mL), levels of PAI-1, uPA, and tPA in conditioned supernatant were measured by specific ELISA and Western blotting. Levels of PAI-1 and uPA mRNA were measured by quantitative RT-PCR., Results: In the cultured term DCs, ELISA measurements indicated that basal output of PAI-1 was about 2 logs higher than that of either uPA or tPA (2.5 +/- 0.7 ng/mL per microg protein, 13.4 +/- 6.3 pg/mL per microg protein, and 25.4 +/- 10.8 pg/mL per microg protein, respectively). Although E2 alone did not affect PAI-1 output, MPA and E2+MPA significantly enhanced PAI-1 production (2.5 +/- 0.7 vs 8.2 +/- 2.0 ng/mL per microg protein for E2+MPA [3.3-fold]; P < .01). By contrast, uPA output was inhibited by exposure to MPA (13.4 +/- 6.3 vs 2.6 +/- 1.1 pg/mL per microg protein [0.2-fold]; P < .05), whereas tPA production was not affected by MPA. Thrombin did not significantly affect uPA and tPA production by term DCs. In contrast, in E2+MPA-treated term DCs, thrombin, a hemostatic proinflammatory cytokine, selectively increased PAI-1 output in a dose-dependent fashion, which could be blocked by the selective thrombin inhibitor, hirudin. Western blotting confirmed the effects of MPA and thrombin in elevating secreted levels of PAI-1. Unlike the increase in PAI-1 output elicited by thrombin, term DCs were unresponsive to either of the classic proinflammatory cytokines, TNFalpha or IL-1beta. Corresponding effects on PAI-1 mRNA levels were elicited by MPA and thrombin as seen for PAI-1 protein expression, suggesting that these up-regulatory effects are transcriptionally mediated., Conclusion: Progestin enhanced PAI-1 and inhibited uPA expression by term DCs, which may explain in part the pregnancy-prolonging properties of progesterone as a consequence of inhibited proteolytic activity at the maternal-fetal interface. Thrombin augmented PAI-1 expression in the absence of increased uPA or tPA expression by term DCs, suggesting that abruption-associated decidual proteolysis and preterm labor is mediated primarily by thrombin-enhanced matrix metalloproteinase expression rather than an indirect effect on the plasminogen activator/inhibitor system.

Objective: Receptor for advanced glycation end products (RAGE) is a multiligand cell-surface receptor part of the immunoglobulin superfamily with crucial roles in inflammation. S100A12/ENRAGE, a biomarker of amniotic fluid (AF) inflammation, is a ligand for RAGE. sRAGE, a competitive soluble RAGE receptor, inhibits RAGE ligands. Here we aimed to investigate the presence and changes in components of the RAGE system in women with intra-amniotic infection and inflammation., Study Design: AF was retrieved by amniocentesis in 113 women stratified as follows: (1) positive AF culture (+AFC; GA = 27 [20-33] wk; n = 27); (2) negative AF culture (-AFC; GA = 30 [20-36] wk; n = 27); (3) second trimester control (2T-CRL; GA = 19 [15-25] wk; n = 31); (4) third trimester control (3T-CRL; GA = 36 [31-38] wk; n = 28). We used mass spectrometry (SELDI) to detect S100A12/ENRAGE in AF. sRAGE levels were measured using specific immunoassays. Placental pathology was interpreted in relationship to the presence or absence of histologic acute inflammation and immunoreactivity of S100A12/ENRAGE and RAGE. mRNA expression of S100A12/ENRAGE, sRAGE, and RAGE in amniochorion and placental villous tissue was investigated using quantitative real-time polymerase chain reaction (PCR)., Results: Presence of the S100A12/ENRAGE biomarker SELDI peak was confirmed in 70% of the +AFC but in only 10% of the -AFC samples (P < .001). The inflammatory biomarker was absent in all control samples. We further determined that the competitive inhibitor sRAGE is temporally regulated during gestation and that its AF levels are not influenced by the presence of either intra-amniotic infection or inflammation. Histologic choriamnionitis associated with intense staining for S100A12/ENRAGE, particularly in inflammatory cells. The immunoreactivity for extracellular domain of RAGE was localized exclusively to amnion epithelial, decidual, and extravillous trophoblast cells. Yet, acute histologic chorioamnionitis was related to increased gene expression of S100A12/ENRAGE in fetal membranes and decreased sRAGE and RAGE in the placenta., Conclusion: The S100A12/ENRAGE system is markedly upregulated in women with intra-amniotic infection and correlates with the degree of inflammation. Further studies remain to elucidate whether the gestational age dependence of the inhibitor molecule sRAGE may explain the higher incidence of infection-related preterm deliveries and especially rupture of the membranes at earlier gestational age.

Objective: We hypothesized that nitric oxide (NO) inhibition has synergistic effects with chronic hypoxia in altering maternal serum levels of soluble fms-like tyrosine kinase 1 (sFlt-1), vascular endothelial growth factor (VEGF), and placental growth factor (PlGF). We tested our hypothesis in a rodent model of intrauterine growth restriction induced by chronic hypoxia and NO inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME)., Study Design: Timed pregnant adult Sprague-Dawley rats were assigned to the following groups: (1) 20% (oxygen) O2 + saline (n = 7); (2) 20% O2 + L-NAME (n = 8); (3) 14% O2 + saline (n = 5); (4) 14% O2 + L-NAME (n = 5); (5) 10% O2 + saline (n = 6); and (6) 10% O2 + L-NAME (n = 6). Seven nulliparous females served as nonpregnant controls. L-NAME (50 mg/rat/day) or saline was administered via subcutaneous osmotic pumps, inserted on day 17 of gestation. A hypoxic chamber was used to assure mild (14% O2) or severe (10% O2) hypoxic environment after surgical placement of the minipumps and until the animals were killed on day 21 of gestation before the onset of labor. Maternal blood was collected preceding death. Free serum levels of VEGF, PlGF, and sFlt-1 were measured by highly specific immunoassays. Two composite indices were calculated (sFV: log [(sFlt-1)/VEGF] and sFP: log [(sFlt-1)/PlGF] and compared among groups., Results: Fetal growth restriction was induced by both severe hypoxia (10% O2) and L-NAME infusion (2-way analysis of variance, P = .02 O2 levels, P < .001 L-NAME), whereas their combination proved to be the most damaging (P < .001). Pregnancy was characterized by higher maternal serum concentrations of VEGF (P < .001) and PlGF (P < .001), but lower levels of sFlt-1 (P = .037) compared with nonpregnant controls. Serum VEGF levels were not altered by either hypoxia or L-NAME infusion (P = .348 O2 levels, P = .205 L-NAME). In contrast, L-NAME significantly increased sFlt-1 serum levels independent of O2 levels (P = .032, L-NAME treatment, P = .991 O2 levels). Chronic hypoxia significantly decreases the circulating levels of PlGF (P < .001) independent of L-NAME treatment. The sFV ratio was neither altered by hypoxia nor by L-NAME infusion. In contrast, the sFP ratio was significantly increased by both L-NAME (P < .001) and severe hypoxia (P < .001), but the effect was not synergistic (P = .655)., Conclusion: Chronic NO inhibition as well as hypoxia induce fetal growth restriction and significantly change maternal circulating levels of sFlt-1 and PlGF, but not of VEGF. The primary effect of chronic hypoxia is in decreasing circulating levels of PlGF that contrasts with that of NO inhibition, which selectively increases sFlt-1 levels. Their effect is thus not synergistic, suggesting independent pathways.

Objective: Elevation of total serum inhibin A and activin A has been interpreted as evidence of placental dysfunction in women who develop pre-eclampsia. We sought to evaluate serum and urine levels of inhibin A and free activin A in normal and hypertensive pregnancies., Study Design: Inhibin A and free activin A were measured by immunoassay in simultaneously collected serum and urine samples from 75 women: (1) severe pre-eclampsia (n = 30); (2) mild pre-eclampsia (n = 11); (3) chronic hypertension (n = 9); (4) pregnant control women (n = 16); and (5) nonpregnant control women (n = 9). Urine levels were normalized to milligrams urine creatinine, and fractional excretions were calculated., Results: Serum and urine inhibin A were increased and fractional excretion was decreased in pregnancy. Serum, urine, and fractional excretion of inhibin A were increased in severe pre-eclampsia, compared with other gravidas. The only difference observed in free activin A was a decrease in serum free activin A in chronic hypertension, compared with severe pre-eclampsia and pregnant control women. Urine inhibin A showed the greatest discrimination between severe pre-eclampsia and pregnant control women: a cut-off of 45 pg/mg urine creatinine had 96.8% sensitivity, 87.5% specificity, and 93.6% accuracy. Women with urine inhibin A greater than 90 pg/mg urine creatinine had a 17-fold relative risk (95% confidence interval 9.7-459.5) of a clinically indicated delivery due to pre-eclampsia., Conclusion: Serum and urine levels of inhibin A are altered in severe pre-eclampsia. Urine inhibin A may have application in the diagnosis and management of pre-eclampsia. Those with chronic hypertension have lower serum but not urine free activin A levels, compared with severe pre-eclampsia and mild pre-eclampsia.

Objective: Five distinct lactate dehydrogenase isoenzymes have been described. We sought to illustrate the specific amniotic fluid lactate dehydrogenase isoenzyme activity profiles in women with intra-amniotic infection., Study Design: Amniotic fluid was retrieved from 82 women who were stratified in the following groups: (1) positive amniotic fluid cultures (n = 23 women; gestational age, 26 weeks [range, 21-32 weeks]); (2) negative amniotic fluid cultures (n = 22 women; gestational age, 30 weeks [range, 16-36 weeks]); (3) second trimester control (normal genetic karyotype; n = 17 women; gestational age, 18 weeks [range, 16-22 weeks]); and (4) third trimester control (fetal lung maturity testing; n = 20 women; gestational age, 36 weeks [range, 31-38 weeks]). The optical density of each isoform was determined relative to a standard with 5 known lactate dehydrogenase isoenzyme activities. Total lactate dehydrogenase activity was measured by the clinical laboratory immediately after retrieval and by a kinetic UV spectrophotometric assay at the time of the isoelectric focusing., Results: Infection increased total lactate dehydrogenase activity: positive amniotic fluid cultures (median, 762.4 [range, 169.3-3374.8]) vs negative amniotic fluid cultures (median, 203.7 [range, 57.8-1939.3]; U/L; P < .001]). Lactate dehydrogenase isoform profiling identified significant and specific increases in lactate dehydrogenase isoforms 3, 4 (P < .01), and 5 (P < .05) in positive amniotic fluid cultures compared to the negative amniotic fluid cultures group. A selective up-regulation in lactate dehydrogenase isoform 5 was identified at term in healthy subjects., Conclusion: Intra-amniotic infection is characterized by an increase in the activities of lactate dehydrogenase isoforms 3, 4, and 5; advancing gestational age demonstrates an up-regulation of isoform 5 only.

Objective: Coupled to hundreds of receptors, G-proteins modulate signal transduction pathways and are important hormonal targets. The first objective was to determine the effect of pregnancy and estradiol on myometrial guanosine triphosphatase activity. The second objective was to begin dissecting the molecular mechanism(s) underlying alterations in guanosine triphosphatase activity., Study Design: Myometrial tissue was obtained from pregnant, nonpregnant, and ovariectomized untreated and estradiol-treated guinea pigs. Myometrial membranes were prepared by homogenization and differential centrifugation. Basal high-affinity specific guanosine triphosphatase activity was quantitated by enzymatic assay and expressed in rhomol 32Pi per milligram protein per minute. Guanosine triphosphatase activity was stimulated using oxytocin, isoproterenol, and prostaglandin F2alpha. Specific G-protein subunits were quantitated using Western blots. G-protein associated gene expression was semiquantitated using HGU133A gene array chips from Affymetrix., Results: Basal myometrial guanosine triphosphatase activity was increased in pregnant compared with nonpregnant animals. Estradiol increased basal myometrial guanosine triphosphatase activity, compared with untreated controls. The effect of estradiol on stimulated activity was agonist dependent. Both Galphas and Galphai isoform 1 protein levels were increased in myometrium from late pregnant compared with nonpregnant animals. By late gestation, the messenger ribonucleic acid levels of those genes were unaltered, compared with the nonpregnant animal. In general, the impact of pregnancy on G-protein family member gene messenger ribonucleic acid expression was modest. Only the small guanosine triphosphatase Rap1b demonstrated altered expression more than 2-fold during either myometrial quiescence (midpregnancy) or activation (term pregnancy) (up 3-fold during quiescence). Genomic network analyses revealed that the expression of another small guanosine triphosphatase, Rab7, was exclusively up-regulated (80%) during quiescence. During late pregnancy, network analysis showed that only G-protein beta was exclusively altered (up-regulated). Estradiol mimicked the pregnancy effect on both transcription and translation of G-protein family members for some but not all potentially relevant genes., Conclusion: The increase in functional myometrial guanosine triphosphatase activity during pregnancy may reflect increased synthesis of 1 or more small guanosine triphosphatase.

Objective: The remodeling of uterine connective tissue during labor can lead to the reorganization of the extracellular matrix that, in turn, may influence the biomechanical properties of the myometrial wall. We hypothesized that the stretching of the lower uterine segment in laboring women with dystocia changes the viscoelastic properties of the uterine wall., Study Design: We tested the tensile strength of lower uterine segment myometrium in 68 pregnant women at term. The biomechanical, structural, and biochemical properties were compared among 3 groups: (1) 39 laboring women who underwent primary low-transverse cesarean delivery for labor dystocia, (2) 12 nonlaboring women who underwent primary elective low-transverse cesarean delivery and (3) 17 women who underwent an elective repeat low-transverse cesarean delivery at term. The tensile properties were quantitated with a stretching regimen that was designed to mimic the conditions of labor. Parameters such as slope, yield point, and break point were recorded, analyzed, and interpreted. Biochemical properties were determined by the measurement of the sulfated glycosaminoglycans, hydroxyproline, and pyridinoline-deoxypyridinoline. Histologic properties of the connective tissue were assessed by collagen birefringence. Lastly, the association between these properties and biomechanical responses were compared among groups., Results: Lower uterine segment myometrium specimens obtained from laboring women were stiffer compared with specimens from women who were not in labor (P = .013) or had scarred myometrium (P < .001). The force that was required to reach the yield point was similar between labor and nonlabor groups (P = .216). Likewise, a previous lower uterine segment scar did not alter the yield point. The break point was similar among all groups (P = .317). Sulfated glycosaminoglycan levels were unaffected by labor or scarring (P = .354). Scarred lower uterine segment myometrium had a higher collagen content compared with unscarred myometrium specimens that were obtained during labor (P = .025). Although there were similar degrees of collagen cross-linking among groups (P = .212), there was lower collagen birefringence in myometrium from laboring women compared with nonlaboring women (P < .001)., Conclusion: Labor alters the viscoelastic properties of myometrium. Lower uterine segment myometrium is stiffest in women with dysfunctional labor compared with nonlabor control subjects. Labor and scarring also alter the pattern of collagen birefringence. Similar collagen cross-linking among the study groups may explain the reason that the breaking strength of the tissue is not altered by the state of labor and the reason that the rupture of the uterine scar is a rare event.

Objective: We sought to identify the use of vaginal amniotic fluid (vAF) glucose measurements in predicting infection of the amniotic fluid retrieved by transabdominal amniocentesis (aAF) in women with preterm premature rupture of the membranes (PPROM)., Study Design: Fluid was retrieved by aAF was retreived from 35 consecutive women with PPROM on whom an amniocentesis was clinically indicated to rule out intra-amniotic infection/inflammation and successfully completed. aAF was cultured for aerobic, anaerobic bacteria, Ureaplasma and Mycoplasma species. Clinical laboratory analysis for aAF included glucose concentration, Gram stain, lactate dehydrogenase, and white and red blood cell count. vAF was analyzed only for glucose concentration. Glucose concentration for the paired abdominal-vaginal AF samples (aAF-vAF) was determined by using well-established clinical and research laboratory methods. At the end of enrollment we stratified our patients into 2 groups: (1) positive microbial cultures (+)AFC (n = 17, gestational age [GA]: 27.3 +/- 0.7 weeks) or (2) negative microbial cultures (-)AFC (n = 18, GA: 31.3 +/- 0.5 weeks). Cohen kappa measure of concordance and receiver operating characteristic (ROC) curve analysis were used to test the ability of the vaginal "pool" glucose measurements to discriminate between women with positive or negative AF cultures., Results: Women with (+)AFC ruptured and delivered at an earlier GA compared with the (-)AFC group (p < .001). The latency period was similar (P = .35). There was a significant linear correlation between aAF and vAF glucose concentrations (r = 0.783, P < .001). Women with intra-amniotic infection (IAI) had significantly lower aAF [mean +/- SEM (+)AFC: 11.4 +/- 3.2 vs (-)AFC 23.0 +/- 2.8 mg/dL, P = .01] and vAF glucose levels [(+)AFC: 10.1 +/- 2.8 vs (-)AFC: 19.8 +/- 2.9 mg/dL, P = .02] compared with the noninfected group. Cohen kappa measure of concordance indicated "substantial" agreement between aAF and vAF glucose measurements (kappa = 0.719, 95% CI = 0.491-0.947). The sensitivity of the vAF glucose level to detect IAI ranged from 82% to 47%, whereas specificity ranged from 100% to 56% depending on the threshold we used. A vaginal "pool" (vAF) glucose measurement less than 5 mg/dL had 47.1% sensitivity, 100% specificity, 100% positive predictive value, 66.7% negative predictive value, and 74.2% accuracy in identifying women with (+)AFC., Conclusion: Vaginal glucose determination is a readily available, inexpensive, rapid AF marker that can be measured practically in any clinical laboratory. vAF glucose measurements less than 5 mg/dL have predictive value, but low sensitivity for detection of IAI.

Objective: Term labor is associated with global thinning of the myometrium. We hypothesized that a thickened myometrium at the time of preterm premature rupture of membranes (PPROM) predicts less myometrial wall stress and, consequently, a longer latency interval., Study Design: Myometrial thickness was measured prospectively in 76 pregnant women enrolled in the following groups: PPROM (n=28, mean [range], gestational age [GA]: 29.5 weeks [w] [21.0 w-33.0 w]), preterm nonlabor control group (P-CTR), (n=21, GA: 27.5 w [23.0 w-32.0 w]) and term nonlabor control (T-CTR) (n=27, GA: 38.6 w [37.0 w-41.6 w]). All PPROM women had oligohydramnios (AFI: 1.4 cm [0.0 cm-5.1 cm]). MT was measured ultrasonographically at the midanterior, fundal, posterior, and lower uterine segment wall in cases and controls with an intraoperator variability <10%., Results: Women in the PPROM group displayed uniform thickness of the uterine body (mean +/- SEM, anterior: 10.6 +/- 0.6 mm, fundal: 10.7 +/- 0.7 mm, posterior: 8.9 +/- 0.5 mm, P=.078). At midanterior site the myometrium of the PPROM group was thicker compared to both P-CTR (P < .001) and T-CTR (P=.025) groups. This difference was preserved at the fundus (PPROM vs P-CTR, P < .001; PPROM vs T-CTR, P=.015). There was a positive correlation between fundal MT and latency period (r=0.43, P=0.02) that persisted after adjusting for GA (P=.04). A fundal MT less than 12.1 mm was 93.7% sensitive and 63.6% specific for the identification of women whose latency period was less than 120 hours., Conclusion: Significant thickening of the anterior and fundal walls of the uterus follows PPROM. A thick myometrium in nonlaboring patients with PPROM is associated with longer latency interval. Sonographic evaluation of MT may represent an alternative clinical tool for the prediction of a short latency interval in women with PPROM.

Objective: Preeclampsia is an idiopathic multisystem disorder specific to human pregnancy. This study used proteomic analysis of cerebrospinal fluid (CSF) to identify protein biomarkers characteristic of preeclampsia and related to its severity., Study Design: CSF was collected from women diagnosed clinically with severe preeclampsia (sPE: n = 7), mild preeclampsia (mPE: n = 8), and normotensive controls (CRL: n = 8). Samples were subjected to proteomic analysis using surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectroscopy. A discriminative proteomic biomarker profile was extracted by applying Mass Restricted analysis, and a Preeclampsia Proteomic Biomarker (PPB) score developed based on the presence or absence of four discriminatory protein peaks in individual CSF SELDI tracings. In-gel tryptic digests, Western blot analysis, on-chip immunoassays, ELISA, and spectral analysis were used to identify the biomarkers composing the PPB score., Results: PPB score distinguished patients with a clinical diagnosis of sPE from mPE and CRLs. (PPB median [range]: sPE: 4 [0-4] vs mPE: 1 [0-1] vs CRL: 0 [0-0]; P < 0.001). PPB scores were unaffected by parity, magnesium seizure prophylaxis, CSF leukocyte counts, and total protein content. Proteomic identification techniques matched the discriminatory protein peaks to the alpha- and beta-hemoglobin chains. ELISA confirmed that women diagnosed clinically with sPE had significantly higher CSF hemoglobin concentrations than women with mPE or CRL (median [range]: sPE: 6.6 [0.0-10.3] microg/mL vs mPE: 0 [0-1.3] microg/mL vs CRL: 0 [0-0] microg/mL; P < 0.001)., Conclusion: Proteomic analysis of CSF can accurately distinguish sPE from both mPE and CRL. Patients with sPE have nanomolar amounts of free hemoglobin in their CSF. Further studies are needed to confirm these observations and determine their physiologic implications.

Objective: Serum levels of soluble fms-like tyrosine kinase 1 (sFlt-1), vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) are altered in women with clinical preeclampsia. We sought to identify whether similar alterations in urinary levels of these proteins cluster hypertensive disorders in pregnancy, and identify women with severe preeclampsia (sPE)., Study Design: Free urinary levels of sFlt-1, VEGF, and PlGF were measured by immunoassay in 68 women enrolled prospectively in the following groups: nonpregnant reproductive age (NP-CTR n = 14), healthy pregnant control (P-CTR n = 16), pregnant hypertensive and proteinuric women who did not meet criteria for severe preeclampsia (pHTN n = 21), and women with sPE (n = 17)., Results: There was no difference in gestational age at the time of enrollment among groups (median [range]: sPE: 31 [24-40], pHTN: 34 [16-40], P-CTR: 28 [7-39] wks). Urinary excretion of VEGF was significantly increased in sPE women compared with NP-CTR (P = .023), but did not differ among pregnant groups. Urinary PlGF levels were significantly increased in pregnant compared with nonpregnant women, but were decreased in all hypertensive women compared with healthy P-CTR (P < .001). Urinary sFlt-1 concentrations were significantly increased in women with sPE relative to all other groups (P < .001). pHTN women had higher sFlt-1 urinary output compared with P-CTR group (P = .001). A cutoff >2.1 in the ratio log [sFlt-1/PlGF] had 88.2% sensitivity and 100% specificity in differentiating women with sPE from normotensive controls. We also described that the log[sFlt-1/PlGF] ratio identified women with sPE better than proteinuria alone (P = .03). Our regression model revealed that uric acid correlated best with log[sFlt-1/PlGF] ratio (r = 0.628; P = .005)., Conclusion: sPE is associated with increased urinary output of the antiangiogenic factor sFlt-1 and a decreased output of PlGF at the time of clinical manifestation, providing a rapid noninvasive screening of hypertensive women based on a sFlt/PlGF ratio. This ratio may be used as representation for severity of the disease, and appears to be superior to random urinary protein measurements.

Objective: The origin of incompetent cervix is multifactorial, and the success of rescue cerclage is unpredictable. We tested amniotic fluid from women who were preparing to undergo rescue cerclage for proteomic biomarkers and correlated their presence with clinical outcome., Study Design: Amniocentesis was performed to facilitate rescue cerclage in 37 consecutive women with painless dilation (> 2 cm) and no detectable uterine activity for 4 hours (range, 1-24 hours) before cerclage. Thirty-nine consecutive women with a sonographically normal pregnancy and cervix who underwent amniocentesis for chromosomal testing during the same study interval at the same clinical site provided the control samples. A proteomic fingerprint was generated with the discarded sample and the Mass-Restricted score (MR score) for inflammation calculated. Peaks corresponding to free hemoglobin chains were sought as evidence of decidual hemorrhage or intra-amniotic bleeding., Results: Amniocentesis was performed at 23.5 weeks in cerclage (mean dilation, 4 cm) versus 19.5 weeks in control subjects. Cerclage subjects were delivered at 28.8 weeks; control subjects were delivered at 39.2 weeks. Thirty-two of 37 of cerclage subjects (86%) were delivered prematurely. Ten of 37 of cerclage subjects (27%), but no control subject, had a MR score that was indicative of inflammation (P < .001). Hemoglobin peaks were present in 12 of 37 of cerclage subject (32%), but no control subjects. Among cerclage subjects, those with a MR score of 3 to 4 were delivered earlier than those with a MR score of 0 to 2 (P < .001). Women with a MR score of 3 to 4 had a shorter latency period (days from amniocentesis to delivery; 3 days) and a shorter percentage of prolongation (1.8%) than women with a MR score of 0 to 2 (35 days; P < .05; 17.9%; P < .05). Women with hemoglobin had a shorter latency period (6 days) and a shorter percentage of prolongation (3.8%) than women without hemoglobin (38 days; P < .05; 21.8%; P < .05). Hemoglobin was present in 7 of 10 of the cerclage subjects (70%) with a MR score of 3 to 4. Women with both a MR score of 3 to 4 and hemoglobin had the shortest intervals to delivery., Conclusion: These findings illustrate 2 pathologic mechanisms that are associated with preterm delivery are also associated with incompetent cervix. Either an intrauterine inflammatory response or decidual hemorrhage predates surgery in one half the women whose condition requires rescue cerclage. The activation of either mechanism predicts cerclage failure.

Objective: The cervix progressively softens during pregnancy to allow stretch without rupture in labor. Cervical softening is the product of complex modifications that include increased proteoglycan-to-collagen ratio, increased hyaluronic acid and water content, and breakdown of collagen by matrix metalloproteases. The relative contribution of collagen breakdown to cervical ripening is unclear. We sought to identify, discriminate, and quantify the physical characteristics of rat cervix during pregnancy, labor, and both before and after exposure to either prostaglandin (PGE(2)) or the collagenolytic enzyme matrix metalloprotease-1 (MMP-1)., Study Design: Cervices were collected from nonpregnant rats in diestrus (n=4) and pregnant rats on d10 (n=4), d16 (n=11), d20 (n=5), and d22 (term) nonlabor (NL: n=4) and d22 in term labor (TL: n=7). Cervices were also collected from a separate group in preterm labor induced by RU486 (PTL: n=10). The effect of PGE(2) on cervical characteristics was determined after intravaginal placement of PGE(2) gel (0.5 mg PGE(2): n=3) or placebo metylcellulose gel (CRL(PG) n=6) for 20 hours before euthanasia on d16. The effect of collagen was determined by incubating in vitro cervices from untreated d16 rats with (MMP-1: n=3) and without (CRL(MMP): n=7) activated collagenase before tensile testing. Tensile properties were quantitated by using Shimadzu EZ-test instrumentation (Shimadzu North America, Columbia, Md) with a stretching regimen that mimicked labor contractions while recording the force opposed by the tissue. Parameters such as the slope (a measure of stiffness), yield point (YP; moment the tissue changes its proprieties from elastic to plastic), and break point (BP; a measure of tissue strength) were recorded and analyzed. The plateau was defined as the phase after YP but before BP., Results: Compared with d16, cervical extensibility increased significantly by d20 (slope d16: 0.41 +/- 0.03 N/mm vs d20: 0.19 +/- 0.05 N/mm, P < .01), and during both PTL (slope: 0.17 +/- 0.03 N/mm) and TL (slope: 0.11 +/- 0.02 N/mm). This increase was mimicked by PGE(2) (slope PGE(2): 0.24 +/- 0.03 vs CRL(PG): 0.40 +/- 0.05 N/mm, P=.04), but not by collagenase (slope MMP-1: 0.35 +/- 0.02 vs CRL(MMP): 0.38 +/- 0.05 N/mm, P>.05). YP was significantly reduced as pregnancy advanced, whereas BP increased, suggesting both increased plasticity (compliance) and strength. However, the plateau length increased 3-fold both by d20 and after PGE(2). In contrast, the addition of MMP-1 reduced the plateau. BP occurred significantly earlier in collagenase-treated tissues, but later in PTL-, TL-, and PGE(2)-treated cervices., Conclusion: The changes in physical properties of the rat cervix during physiologic ripening are similar to those induced by PGE(2) and RU486, and consist of increased extensibility, compliance, and strength. These changes cannot be attributed to increased collagenase activity, which would decrease tissue compliance and strength.

Background: Innate immunity evolved to eliminate microorganisms before, or after their entry into the tissues, but before enough antigen is available to activate an adaptive, immune response. Innate immunity is so successful that the majority of encountered microbes are neutralized. The beta-defensins are antimicrobial peptides produced by skin and mucosal surfaces and are an integral part of the innate immune system. The ability of the amnion cells, which are epithelial derivatives, to produce antimicrobial beta-defensins has not been explored., Objective: This study was undertaken to test the hypothesis that amnion cells synthesize beta-defensins under either basal or stimulated conditions., Methods: Amnion epithelial FL cells (ATCC CCL 62) were cultured in Ham's F12 and Dulbecco's modified Eagle medium plus 10% fetal calf serum until confluence, then replated into 24-well plates at 1.5 million cells per well. Cells from triplicate wells were harvested after 1, 3, 6, and 24 hours of exposure to microbial wall components (lipopolysaccharide [LPS]: 1 microg/mL or peptidoglycan [PG]: 10 microg/mL). Reverse transcription real-time polymerase chain reaction was performed with the use of human-specific primers for beta1, beta2, beta3, and beta4 defensins to compare basal messenger RNA (mRNA) levels of defensins and in response to treatment. beta-actin was used for standardization. Protein expression was investigated by immunofluorescence of the cells in culture, and by immunohistochemistry in paraffin sections of human fetal membranes from pregnancies with or without histologic chorioamnionitis., Results: Amnion FL cells expressed mRNA for all known beta-defensins with beta3-defensin mRNA levels significantly higher compared with others ( P < .001, 1-way analysis of variance [ANOVA]). beta3 was the only beta-defensin whose mRNA was upregulated in response to the microbial mimics LPS (1-way ANOVA, P = .019) and PG (1-way ANOVA, P = .011). Immunofluorescence confirmed that beta3-defensin protein was present in cultured amnion cells, and upregulated in response to PG and LPS in distinct cells. Similarly, in tissue sections of human fetal membranes amnion epithelium was intensely positive for beta3-defensin protein by immunohistochemistry. Conspicuous beta3-defensin staining was also detected in the chorio-decidua., Conclusion: Amnion cells have the ability to produce beta-defensins. The beta3-defensin appears to be the predominant epithelial defensin expressed. Its induction by microbial mimics suggests that the amniotic epithelium may play a role in the innate immunity of the amniotic cavity.

Objective: Cyclic nucleotide phosphodiesterases (PDEs) are a diverse enzyme group with multiple regulatory properties and wide tissue distribution. Such activity includes cyclic adenosine (cAMP) and guanosine monophosphate (cGMP) breakdown. The type 5 isoform (PDE-5, cGMP specific) is the target of specific antagonists (ie, sildenafil, Viagra). We tested the hypothesis that PDE-5 is present in rat myometrium and modulates myometrial activity., Study Design: Full-thickness uterine wall was collected from nonpregnant (n=3) and pregnant Sprague-Dawley rats on days 10 (n=4), 17 (n=6), 22 nonlabor (n=5), and 22 during term labor (TL, n=4). Preterm labor (PTL, n=3) was induced in some animals on day 16 with 15 mg/kg mifepristone (RU 486). Tissue samples were prepared for Western blotting using a monoclonal antibody against rodent PDE-5. In a second series, cumulative doses of sildenafil (0.005, 0.05, 0.5, 5 mg/kg, intraperitoneal) were administered and the effect on uterine contractility recorded in vivo during term (TL, n=7) and preterm labor (PTL, n=6). Saline solution-injected rats provided temporal control. Uterine contractility was estimated from intrauterine pressure (IP) measured electronically with a sensor tip pressure catheter. Heart rate was recorded simultaneously using electrodes attached to the chest and connected to the same data acquisition system., Results: PDE-5 immunoreactivity was present in the nonpregnant rat uterus and at all gestational times studied, although the expression was unaffected by either pregnancy or the state of labor (preterm or term). A dominant antibody-specific band was identified at 86 kd in the uterine samples, contrasting with lung where the 100-kd PDE-5 isoform was most abundant. Two additional lower molecular weight (55 and 32 kd) bands were also identified as antibody specific. Despite the lack of change in PDE-5 during pregnancy, sildenafil reduced IP during TL and PTL beginning at 0.5 mg/kg. The highest dose of sildenafil reduced IP during both TL and PTL by 45% and 59% of baseline, respectively (two-way analysis of variance, P<.01). This effect was not accompanied by changes in heart rate., Conclusion: PDE-5 is constitutively present in the rat uterine wall. There was no observed change in the PDE-5 protein expression throughout pregnancy. In contrast to the lung, the uterus expresses an 80-kd PDE-5 isoform. Sildenafil in pharmacologic doses inhibits mechanical uterine activity and might be of benefit if selectively used for treatment of preterm labor.

Objective: Oxidative stress occurs when the production of damaging free radicals and other oxidative molecules exceeds the capacity of the body's antioxidant defenses. Oxidative stress is implicated in diseases that are associated with prematurity (such as retinopathy, cerebral palsy, intraventricular hemorrhage, and necrotizing enterocolitis). Nonenzymatic antioxidant reserve is the first line of defense against free radicals. We hypothesized that an in utero redox imbalance because of stress would diminish the fetal antioxidant reserve. We tested aspects of this hypothesis by investigating whether the presence of labor or gestational age at delivery (term vs preterm) alters the maternal/fetal nonenzymatic antioxidant reserve peripartum., Study Design: Fetal redox consumption was calculated from the difference in the nonenzymatic antioxidant reserve that was measured in umbilical venous and arterial blood that was collected prospectively at delivery from 39 newborn infants. Eight women were delivered at term by elective cesarean delivery in the absence of labor; 31 women labored either at term (n = 20) or preterm (<37 weeks, n = 11). Maternal venous blood was collected on admission and within 1 hour of delivery. Nonenzymatic antioxidant reserve was measured in the plasma and red blood cells of each specimen by the quantitation of glutathione content (glutathione in red blood cell lysate) and the plasma total free radical-trapping antioxidant potential. Glutathione was measured with the use of a colorimetric assay and expressed in nanomoles per milligram of hemoglobin. The plasma total radical-trapping antioxidant potential was estimated with the use of a controlled, kinetic assay based on the time that was required to inhibit peroxyl-free radical generated under controlled conditions. The differences between both umbilical venous and umbilical arterial total radical-trapping antioxidant potential and glutathione were computed to estimate fetal nonenzymatic antioxidant reserve consumption. The differences between maternal total radical-trapping antioxidant potential and glutathione before and after delivery were computed to estimate maternal peripartal nonenzymatic antioxidant reserve consumption., Results: Fetal red blood cell glutathione content was significantly greater than maternal red blood cell glutathione content, independent of delivery route. The calculation of the fetal nonenzymatic antioxidant reserve consumption and maternal peripartal nonenzymatic antioxidant reserve consumption revealed that women who labored at term experienced an up-regulation in red blood cell glutathione content, while their fetuses had significantly lower red blood cell glutathione consumption. In contrast, there was consumption of plasma antioxidants in preterm fetuses, as illustrated by a doubling of the fetal nonenzymatic antioxidant reserve consumption (elective cesarean delivery in the absence of labor, 0.9 +/- 0.5 min/microL; term labor, 1.0 +/- 0.1 min/microL; preterm labor, 2.0 +/- 0.4 min/microL; one-way analysis of variance; P =.04). This was mostly due to a lower umbilical arterial total radical-trapping antioxidant potential in preterm versus term fetuses (umbilical arterial, 3.3 min/microL versus umbilical venous 5.4 min/microL; paired t test; P =.001; power, 0.98). Generally, maternal total radical-trapping antioxidant potential remained unchanged peripartum., Conclusion: Term labor triggers a compensatory up-regulation of nonenzymatic antioxidant reserve in the fetal red blood cell compartment that may act to protect against the relative hyperoxia that is experienced by the newborn infant at birth. In contrast, the decreased nonenzymatic antioxidant reserve in the fetal red blood cell and plasma compartments after preterm labor and delivery would enhance the vulnerability to free radical damage of the preterm neonate. These findings suggest that the two compartments of nonenzymatic antioxidant reserve have distinct physiologic roles in the peripartal defense against free radicals and that their development is, in some fashion, ontogenes, in some fashion, ontogenetically regulated.

Objective: Most fetuses in the occipitoposterior position rotate spontaneously after striking the pelvic floor. The increased prevalence of prolonged labor, operative delivery, and oxytocin augmentation in women with an occipitoposterior fetal position seems consistent with decreased uterine contractility. We sought to test the hypothesis that women with a persistent occipitoposterior fetal position have inadequate intrauterine pressure., Study Design: Intrauterine pressure was measured prospectively electronically in 94 women whose labor pain was controlled by patient-requested epidural analgesia. Eleven women (12%) were delivered as a persistent occipitoposterior fetal position. In a nested case-control study, these women were compared with 22 women who were delivered as an occipitoanterior fetal position who were matched for age, parity, gestational age, cervical examination at study enrollment, and body mass index. The intrauterine pressure measurements were initiated during the first stage of labor and continued throughout the entire labor process. Women were encouraged in the second stage of labor, after a period of recording baseline contractility, to push using a standardized Valsalva maneuver once the vertex reached the +2 station. The area under the intrauterine pressure curve (integral) was used to estimate uterine contractility and expulsive performances., Results: Five women (45%) in the occipitoposterior group required operative delivery. The average duration of the second stage of labor in the occipitoposterior group was 91.4 +/- 23.2 minutes compared with 51.7 +/- 6.6 minutes in the occipitoanterior fetal position (P =.04). Ninety percent of women in the occipitoposterior group required oxytocin, compared with 59% of the women in the occipitoanterior group (P =.11). There were no differences in uterine contractility between occipitoposterior and occipitoanterior groups during either the first stage of labor (integral mean +/- SEM: occipitoposterior [1685.3 +/- 194.6 mm Hg. s] vs occipitoanterior fetal position [1700.8 +/- 128.9 mm Hg. s, P =.98]) or second stages of labor (occipitoposterior [1952.6 +/- 186.5 mm Hg. s] vs occipitoanterior fetal position [1740.8 +/- 104.3 mm Hg. s, P =.46]). Further, there were no significant differences in pushing performances between the occipitoposterior and occipitoanterior groups (Valsalva maneuver: occipitoposterior 2864.9 +/- 328.8 mm Hg. s] vs occipitoanterior [2898.6 +/- 222.2 mm Hg. s, P =.90])., Conclusion: Women who were delivered as a persistent occipitoposterior fetal position do not have lower intrauterine pressure levels immediately before or during the second stage of labor.

Objective: Morphologic studies suggest dramatic, asymmetric uterine growth during pregnancy that is caused by muscle cell hypertrophy. This growth is most marked at the fundus. Our objective was to evaluate sonographically the in vivo changes in myometrial thickness during active labor, second-stage labor, and after delivery., Study Design: Abdominal ultrasound scans were performed on 52 term pregnant women to investigate the dynamic changes in myometrial thickness during the active and second stages of labor and immediately after delivery. Twenty-six women (mean +/- SEM gestational age, 39.09 +/- 0.3 weeks) were in active labor (cervical dilatation >4 cm with regular uterine contractions). An additional 26 nonlaboring women (gestational age, 39.8 +/- 0.2 weeks) provided control measurements. The myometrium was defined sonographically as the echo homogeneous layer between the serosa and the decidua. Myometrial thickness was measured at the low segment and mid anterior, fundal, and posterior uterine walls by the same observer. Myometrial thickness was also measured during uterine contractions and after artificial rupture of the amniotic membranes. All laboring women had uncomplicated labor patterns when studied and were delivered spontaneously., Results: The myometrium was significantly thinner during active labor compared with nonlabor at each site studied: midanterior (mean [+/-SEM] myometrial thickness, 5.8 +/- 0.27 vs 8.83 +/- 0.51 mm; t test, P <.001), fundus (mean myometrial thickness, 6.78 +/- 0.32 vs 8.49 +/- 0.35 mm; P =.0015), and posterior (mean myometrial thickness, 6.22 +/- 0.34 vs 8.12 +/- 0.30 mm; P <.001). However, myometrial thickness did not differ among sites within the two groups. The thickness of the low segment was not affected by labor status (nonlabor, 4.68 +/- 0.48 vs labor, 4.66 +/- 0.37 mm; P =.97). Similarly, the myometrial thickness of the anterior uterine wall was unaffected by contractions (no contractions, 5.56 +/- 0.2 vs contractions, 5.68 +/- 0.22 mm; t test, P =.654). There was no change in myometrial thickness measured immediately before and after rupture of the amniotic membranes, despite a significant decrease of the amniotic fluid index. There was significant thickening of the anterior and fundal myometrium during the second stage of labor after the fetal head descended to +3 station by digital examination (anterior, 12.99 +/- 0.60 vs 5.8 +/- 0.27 mm; t test, P <.001; fundus, 10.61 +/- 1.63 vs 6.78 +/- 0.32 mm; t test, P =.04). Valsalva maneuver (pushing) during contractions did not affect myometrial thickness at the fundus (between contractions, 10.61 +/- 1.63 vs pushing, 10.76 +/- 1.95 mm; t test, P =.99). Immediately after delivery, the myometrial thickness at the placental insertion site was the thinnest. After completion of the third stage of labor, the uterine fundus remained significantly thinner than the anterior and posterior walls (fundus, 27.37 +/- 3.5 mm vs anterior, 40.94 +/- 3.5 vs posterior, 42.34 +/- 2.44; one-way analysis of variance, P =.02)., Conclusion: There is significant and widespread thinning of the myometrium during active labor. Descent of the fetal head during the second stage of labor is associated with a significant relative thickening of the anterior and fundal myometrium. After delivery, the relationship reverses. These findings suggest the directionality of the expulsive force vectors (fundal dominance) is not determined by asymmetric myometrial growth but, rather, may be a function of increased "myometrial mass" that results from increased surface area at the fundus.

Objective: Intrauterine and maternal systemic infections are proposed causes of preterm labor. The resulting prematurity is associated with 75% of infant mortality and 50% of long-term neurologic handicaps. We hypothesize that free radicals generated in large quantities during an inflammatory response shift the fetomaternal redox balance to an oxidative state, compromising the fetus. Thus, if our working hypothesis is correct, selective inactivation of free radicals with N-acetylcysteine (NAC), an antioxidant and glutathione (GSH) precursor, would improve the outcome of preterm deliveries associated with inflammation. We tested aspects of this hypothesis in an animal model of preterm labor and fetal damage (death)., Study Design: NAC (1 g/kg) was administered orally to C57Bl/6 mice injected intraperitoneally with either 10 microg lipopolysaccharide (LPS) or saline solution (CRL) on day 16 of gestation. The latency period (time from injection to delivery of the first pup) and fetal viability were recorded. To discriminate between an effect of prematurity from an effect of inflammation, and to document any improvement in survival, mice were killed at 3, 6, and 16 hours after injection. Maternal and fetal redox states were approximated by measuring hepatic GSH., Results: Each C57Bl/6 LPS-treated mouse delivered prematurely after a significantly shorter latency period (LPS: 16.8 hours [95% CI 15.9-17.6] vs CRL: 54.7 hours [95% CI 43.8-65.5]). NAC doubled the latency interval of LPS-treated animals to 35.2 hours (95% CI 21.0-49.2). LPS alone resulted in a 100% rate of stillbirth. Fifty-eight percent of fetuses were already dead 16 hours after LPS. In contrast, only 33% of fetuses were dead 16 hours after LPS (P =.001) when NAC was given. LPS was followed by a reduction in maternal (LPS: 26.3 nmol/mg [95% CI 19.9-32.8] vs CRL: 41.3 nmol/mg [95% CI 34.7-47.9, P <.01]) and fetal GSH (LPS: 19.7 nmol/mg [95% CI 11.7-27.8] vs CRL: 34.5 nmol/mg [95% CI 32.0-37.0, P <.001]). This decline was reversed by NAC (NAC/LPS maternal GSH: 37.0 nmol/mg [95% CI 22.5-51.5] and fetal GSH: 28.4 nmol/mg [95% CI 22.8-33.9]). Importantly, maternal liver GSH impacted on fetal survival. NAC/LPS mothers with living pups 16 hours after LPS had significantly higher liver GSH compared with NAC/LPS mothers whose pups died in utero. In fact, all NAC-treated mice whose hepatic GSH exceeded 20 nmol/mg had living fetuses at 16 hours., Conclusion: Maternal inflammation in C57Bl/6 mice results in oxidative stress associated with maternal and fetal GSH depletion. Oxidative stress damages the fetus independent of prematurity. Restoration of maternal and fetal oxidative balance by NAC protects the fetus and reduces the rate of preterm birth.

Nitroglycerin is administered intravenously in acute obstetric emergencies to relax the uterus. However, complications (eg, hypotension, acute uterine bleeding) are frequent, which prompted a search for alternative routes of administration. We hypothesized that the sublingual administration of nitroglycerin would reduce uterine tone and contractility with few complications. Intrauterine pressure was measured in 12 women who were actively laboring (>4 cm dilatation, regular contractions) with epidural analgesia and who were alert and responsive throughout the study. In a double-blind fashion, subjects were randomized to receive either placebo or sublingual nitroglycerin (3 doses, 800 microg each) 10 minutes apart. The obstetric anesthesiologist continuously monitored maternal blood pressure and fetal heart rate. Cervical dilatation was assessed at the beginning and the end of the protocol. The area under the intrauterine pressure curve (integral) was used to estimate uterine contractility. Intrauterine pressure was analyzed before the randomization code was broken. Nitroglycerin did not alter the intrauterine pressure integral after the first dose (placebo, 3147 mm Hg x s [95% CI, 2206-4088] vs nitroglycerin, 4146 mm Hg x s [95% CI, 2451-5841]; P =.22), second dose (placebo, 3123 mm Hg x s [95% CI, 2447-3799] vs nitroglycerin, 3611 mm Hg x s [95% CI, 2723-4499]; P =.28), or third dose (placebo, 3303 mm Hg x s [95% CI, 2616-3990] vs nitroglycerin, 3810 mm Hg x s [95% CI, 2306-5314]; P =.45). Cervical dilation, basal uterine tone, duration and frequency of uterine contractions, or fetal heart rhythm remained unaffected. Maternal mean arterial pressure decreased significantly after nitroglycerin was administered. All women were delivered vaginally without intervention. Three doses of sublingual nitroglycerin (800 microg per dose) reduce neither uterine activity nor tone, despite lowering maternal blood pressure. If a clinical option, sublingual nitroglycerin will require a higher dose, which would place mother and fetus at risk for complication.

Objective: It is believed that delivery is faster if women are instructed to voluntarily bear down in synchrony with their uterine contractions. Confronted by the large variance in the duration of the second stage of labor, many clinicians attribute a "fast" or a "short" expulsion time solely to the patient's willingness to cooperate or to the strength of epidural anesthesia if it is a factor. Yet, knowledge of pushing performance and the factors affecting it remain limited. We investigated the maternal, fetal, and labor characteristics that influence the maternal "pushing performance" and sought to design a predictive index that prospectively identified "high" versus "low" pushing performers., Study Design: Intrauterine pressure (IP) was prospectively measured during the second stage of labor in 52 women recruited at one North American hospital. Recordings were begun after documentation of full cervical dilatation and descent of the fetal head to +2 station (on a -3/+3 scale). Each woman acted as her own control, received epidural anesthesia, and was alert and responsive throughout the study. Pushing (closed glottis technique) was performed in a standardized fashion. Multivariate analysis with linear regression was applied to identify significant associations between maternal, fetal, or labor characteristics as the independent variables and the percent increase in IP consequent to active pushing as the dependent variable., Results: Women in labor increase their IP 62% by actively pushing with a contraction during the second stage. A scattergram of the individual percent increase above the baseline IP integral revealed that for some women, pushing more readily increased their IP than it did for others (range, 0% to 192%). The percent increase was best calculated by a linear combination of myometrial thickness, estimated fetal weight, the maternal body mass index, and the obstetric need for labor augmentation (P =.007, r = 0.52, power = 0.975). A 66% change in IP provided the best separation between high and low pushing performance. Myometrial thickness provided the single strongest contribution to the regression equation's predictive value (P =.01, r = -0.36). A myometrial thickness of 6 mm had a specificity of 88% (but only 53% sensitivity) for the identification of women able to increase their IP by 66% over baseline., Conclusions: In women in labor who have received epidural anesthesia, the efficiency with which maternal expulsive efforts are converted into increased IP is directly related to the patient's body mass index but inversely related to myometrial thickness, the sonographic estimate of fetal weight, and the need for labor augmentation.