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Objectives: T2*‐weighted magnetic resonance imaging (MRI) sequences have been identified as non‐invasive tools with which to study placental oxygenation in vivo. This study aimed to use these to investigate both static and dynamic responses to hyperoxia of the normal placenta across gestation. Methods: We conducted a single‐center prospective study including 52 uncomplicated pregnancies. Two T2*‐weighted sequences (T2* relaxometry) were performed, one before and one after maternal hyperoxia. The distribution of placental T2* values was modeled by fitting a gamma probability density function (T2* ~Γαβ), describing the structure of the histogram using the mean T2* value, the shape parameter (α) and the rate (β). A dynamic acquisition (blood‐oxygen‐level‐dependent (BOLD) MRI) was also performed before and during maternal oxygen supply, until placental oxygen saturation had been achieved. The signal change over time was modeled using a sigmoid function, to determine the intensity of enhancement (ΔBOLD (% with respect to baseline)), a temporal variation coefficient (λ (min–1), controlling the slope of the curve) and the maximum steepness (Vmax (% of placental enhancement/min)). Results: The histogram analysis of the T2* values in normoxia showed a whole‐placenta variation, with a decreasing linear trend in the mean T2* value (Pearson's correlation coefficient (R) = −0.83 (95% CI, −0.9 to −0.71), P < 0.001), along with an increasingly peaked and narrower distribution of T2* values with advancing gestation. After maternal hyperoxia, the mean T2* ratios (mean T2*hyperoxia/mean T2*baseline) were positively correlated with gestational age, while the other histogram parameters remained stable, suggesting a translation of the histogram towards higher values with a similar appearance after maternal hyperoxia. ΔBOLD showed a non‐linear increase across gestation. Conversely, λ showed an inverted trend across gestation, with a weaker correlation (R = −0.33 (95% CI, −0.58 to −0.02), P = 0.04, R2 = 0.1). As a combination of ΔBOLD and λ, the changes in Vmax throughout gestation were influenced mainly by the changes in ΔBOLD and showed a positive non‐linear correlation with gestational age. Conclusions: Our results suggest that the decrease in the T2* placental signal as gestation progresses does not reflect placental dysfunction. The BOLD dynamic signal change is representative of a free‐diffusion model of oxygenation and highlights the increasing differences in oxygen saturation between mother and fetus as gestation progresses (ΔBOLD) and in the placental permeability to oxygen (λ). © 2024 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Synopsis: We introduce a new microflow imaging technique, which can show the blood perfusion and morphological structure of placental villi. [ABSTRACT FROM AUTHOR]

Objectives: Evidence regarding placental function in pregnancies complicated by confined placental mosaicism (CPM) is conflicting. We aimed to compare placental function between CPM and non‐CPM pregnancies prenatally and at birth. A secondary objective was to evaluate the relationship between placental function and chromosomal subtype of CPM. Methods: This was a retrospective study of pregnancies with CPM and control pregnancies delivered at a tertiary hospital in Denmark between 2014 and 2017. Placental volume and placental transverse relaxation time (T2*) were estimated on magnetic resonance imaging (MRI), fetal weight and uterine artery pulsatility index (UtA‐PI) were estimated on ultrasound and fetoplacental ratio was assessed on MRI and at birth. These estimates of placental function were adjusted for gestational age and compared between groups using the Wilcoxon rank‐sum test. Within the group of CPM pregnancies, measures of placental function were compared between those at high risk (chromosome numbers 2, 3, 7, 13 and 16) and those at low risk (chromosome numbers 5, 18 and 45X). Results: A total of 90 pregnancies were included, of which 12 had CPM and 78 were controls. MRI and ultrasound examinations were performed at a median gestational age of 32.6 weeks (interquartile range, 24.7–35.3 weeks). On MRI assessment, CPM placentae were characterized by a lower placental T2* Z‐score (P = 0.004), a lower fetoplacental ratio (P = 0.03) and a higher UtA‐PI Z‐score (P = 0.03), compared with non‐CPM placentae. At birth, the fetoplacental ratio was significantly lower (P = 0.02) and placental weight Z‐score was higher (P = 0.01) in CPM pregnancies compared with non‐CPM pregnancies. High‐risk CPM pregnancies showed a reduced placental T2* Z‐score (P = 0.003), lower birth‐weight Z‐score (P = 0.041), earlier gestational age at delivery (P = 0.019) and higher UtA‐PI Z‐score (P = 0.028) compared with low‐risk CPM pregnancies. Low‐risk CPM pregnancies did not differ in any of these parameters from non‐CPM pregnancies. Conclusions: CPM pregnancies are characterized by an enlarged and dysfunctional placenta. Placental function was highly related to the chromosomal type of CPM; placental dysfunction was seen predominantly in high‐risk CPM pregnancies in which chromosomes 2, 3, 7, 13 or 16 were involved. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Objective: Birth weight, fetal growth and placental function influence cognitive development. The gradient of these associations is understudied, especially among those with a birth weight considered appropriate‐for‐gestational age. The aim of this study was to evaluate the associations between birth‐weight centile and intellectual development in term/near‐term infants across the entire birth‐weight spectrum, in order to provide a basis for better understanding of the long‐term implications of fetal growth restriction and reduced placental function. Methods: This was a population‐based cohort study of 266 440 liveborn singletons from uncomplicated pregnancies, delivered between 36 and 42 weeks of gestation. Perinatal data were obtained from the Dutch Perinatal Registry over the period 2003–2008 and educational data for children aged approximately 12 years were obtained from Statistics Netherlands over the period 2016–2019. Regression analyses were conducted to assess the association of birth‐weight centile with school performance. The primary outcomes were mean school performance score, on a scale of 501–550, and proportion of children who reached higher secondary school level. Results: Mean school performance score increased gradually with increasing birth‐weight centile, from 533.6 in the 1st–5th birth‐weight‐centile group to 536.8 in the 81st–85th birth‐weight‐centile group. Likewise, the proportion of children at higher secondary school level increased with birth‐weight centile, from 43% to 57%. Compared with the 81st–85th birth‐weight‐centile group, mean school performance score and proportion of children at higher secondary school level were significantly lower in all birth‐weight‐centile groups below the 80th centile, after adjusting for confounding factors. Conclusions: Birth‐weight centile is associated positively with school performance at 12 years of age across the entire birth‐weight spectrum, well beyond the conventional and arbitrary cut‐offs for suspected fetal growth restriction. This underlines the importance of developing better tools to diagnose fetal growth restriction and reduced placental function, and to identify those at risk for associated short‐ and long‐term consequences. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Worldwide demand for petroleum products has resulted in increased oil and gas activities in many countries. Conventional and unconventional oil and gas extraction, production, and transport lead to increased levels of petroleum‐derived polycyclic aromatic hydrocarbons (PAHs) in the environment. PAH exposure has profound effects on reproduction by affecting pathways involved in placental trophoblast cell function and impairing normal placental development and function—key contributors to reproductive success. However, other components found in petroleum and wastewaters from oil and gas extraction, including the sulfur‐containing heterocyclic aromatic compounds such as dibenzothiophene (DBT) and its alkylated derivatives, may also impact reproductive success. The goal of this study was to examine the effect of exposure to DBT, a compound commonly detected in the environment, and one of its alkylated analogues, 2,4,7‐trimethyldibenzothiophene (2,4,7‐DBT), on steroidogenic and angiogenic pathways critical for mammalian development in placental trophoblast cells (HTR‐8/SVneo cells). 2,4,7‐DBT but not DBT increased estradiol output in association with increased tube‐like formation (surrogate for angiogenesis). These changes in angiogenesis did not appear to be related to altered expression of the key placental angiogenic gene targets (ANGPTL4, VEGFA, and PGF). Neither compound showed a concentration related effect on progesterone synthesis or its receptor expression. Our results suggest that 2,4,7‐DBT can disrupt key pathways important for placental trophoblast function and highlight the importance of determining the impact of exposure to both parent and alkylated compounds. Further, these data suggest that exposure to sulfur‐containing heterocyclic aromatic compounds may lead to placental dysfunction and impact reproductive success at environmentally relevant levels. Proximity to oil and gas extraction sites has been associated with impaired reproductive success. Oil and gas extraction is associated with increased detection of dibenzothiophene, a sulfur‐containing heterocyclic aromatic compound, and its alkylated congeners in abiotic matrices and wildlife. We demonstrated that 2,4,7‐trimethyldibenzothiophene but not dibenzothiophene caused dysregulated estradiol output and angiogenesis in placental cells. As these outcomes are linked with placental dysfunction, these results highlight the importance of considering the impact of alkylated polycyclic aromatic compounds on mammalian reproduction. [ABSTRACT FROM AUTHOR]

Purpose: Placental function is key for successful human pregnancies. Perfusion may be a sensitive marker for the in vivo assessment of placental function. Arterial spin labeling (ASL) MRI enables noninvasive measurement of tissue perfusion and it was recently suggested that ASL with velocity‐selective (VS) labeling could be advantageous in the placenta. We systematically evaluated essential VS‐ASL sequence parameters to determine optimal settings for efficient placental perfusion measurements. Methods: Eleven pregnant women were scanned at 3T using VS‐ASL with 2D multislice echo planar imaging (EPI)‐readout. One reference VS‐ASL scan was acquired in all subjects; within subgroups the following parameters were systematically varied: cutoff velocity, velocity encoding direction, and inflow time. Visual evaluation and region of interest analyses were performed to compare perfusion signal differences between acquisitions. Results: In all subjects, a perfusion pattern with clear hyperintense focal regions was observed. Perfusion signal decreased with inflow time and cutoff velocity. Subject‐specific dependence on velocity encoding direction was observed. High temporal signal‐to‐noise ratios with high contrast on the perfusion images between the hyperintense regions and placental tissue were seen at ~1.6 cm/s cutoff velocity and ~1000 ms inflow time. Evaluation of measurements at multiple inflow times revealed differences in blood flow dynamics between placental regions. Conclusion: Placental perfusion measurements are feasible at 3T using VS‐ASL with 2D multislice EPI‐readout. A clear dependence of perfusion signal on VS labeling parameters and inflow time was demonstrated. Whereas multiple parameter combinations may advance the interpretation of placental circulation dynamics, this study provides a basis to select an effective set of parameters for the observation of placenta perfusion natural history and its potential pathological changes. [ABSTRACT FROM AUTHOR]

Objective: It has been suggested that the use of Doppler ultrasound in term pregnancies with normal-sized fetuses is able to identify those at high risk of subclinical placental function impairment. The objective of this study was to evaluate the relationship between cerebroplacental ratio (CPR) measured in early labor and perinatal and delivery outcomes in a cohort of uncomplicated singleton term pregnancies.Methods: This was a prospective multicenter observational study conducted at three tertiary centers between January 2016 and July 2017. Low-risk term pregnancies, defined by the absence of maternal morbidity or pregnancy complication, accompanied by normal ultrasound and clinical screening of fetal growth in the third trimester, with spontaneous onset of labor were included. Umbilical artery (UA) and fetal middle cerebral artery (MCA) Doppler was assessed on admission for early labor. All measurements were performed in between uterine contractions and according to international standards. CPR was computed by dividing MCA pulsatility index by UA pulsatility index and converted into multiples of the median (MoM) in order to adjust for gestational age. Doctors and midwives involved in the clinical management of the women were blinded to the results of the Doppler evaluation. Mode of delivery and perinatal outcome were compared between pregnancies with reduced CPR MoM, defined as CPR MoM within the lowest decile of the study population, and those with normal CPR MoM. Receiver-operating characteristics curve analysis was used to assess the predictive performance of CPR for obstetric intervention due to fetal distress and composite adverse perinatal outcome.Results: Overall, 562 women were included. The rate of obstetric intervention for suspected fetal distress in labor was more than three times higher among cases with reduced CPR MoM compared to those with normal CPR MoM (9/54 (16.7%) vs 28/508 (5.5%); P = 0.004). Furthermore, a significantly higher rate of composite adverse perinatal outcome was found in fetuses with CPR MoM < 10th percentile compared to those with CPR MoM ≥ 10th percentile (6/54 (11.1%) vs 19/508 (3.7%); P = 0.012). CPR had low sensitivity and low positive predictive value for prediction of obstetric intervention due to fetal distress (24.3% and 18.0%, respectively) and composite adverse perinatal outcome (24.0% and 11.1%, respectively).Conclusions: Data on a wide cohort of low-risk term pregnancies in early labor showed that, while reduced CPR is associated with a higher risk of obstetric intervention due to fetal distress and composite adverse perinatal outcome, it is a poor predictor of adverse perinatal outcome. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Aim The aim of this research was to study and compare placental elasticity with acoustic radiation force impulse (ARFI) elastography in pre-eclamptic and normal pregnancies. Methods A total of 107 singleton pregnancies in the third trimester (38 healthy control subjects, 34 patients with gestational hypertension, and 35 pre-eclampsia patients) were included in the study. ARFI elastography was used to determine the placental elasticity in the three predetermined regions of the placenta (the fetal edge, maternal edge, and central part of the placenta). The obstetrical data regarding grayscale and Doppler ultrasonography and perinatal outcomes were reviewed. A mean placental shear wave velocity cut-off value that predicts the presence of pre-eclampsia was determined. Results The shear wave elasticity values in the pre-eclampsia group in all three regions were significantly higher than in the gestational hypertension and healthy control groups ( P = 0.001). The most significant difference was found in the peripheral edge of the placenta from the fetal surface in the pre-eclampsia group ( P = 0.001). Conclusion The stiffness of the placenta determined by the ARFI technique is significantly higher in pre-eclampsia patients. ARFI elastography of the placenta might be used as a non-invasive and easy method in the diagnosis and evaluation of pre-eclampsia as a supplement to the already existing methods. [ABSTRACT FROM AUTHOR]

We investigated morphological differences in uterine epithelia of the reproductive cycle between two closely related viviparous skinks, Niveoscincus metallicus (lecithotrophic) and Niveoscincus ocellatus (placentotrophic), which have similar placental complexity but different degrees of placentotrophy. Scanning ( SEM) and transmission electron microscopy ( TEM) revealed that the uterine surface of non-reproductive females of both species is mainly covered by ciliated cells. As vitellogenesis begins, the uterine epithelium consists of ciliated and non-ciliated cells under a thin glycocalyx. Microvilli are greatly reduced at mid-pregnancy, and the uterus differentiates into two structurally distinct regions: the chorioallantoic and the omphaloplacenta. At late stages of pregnancy, the uterine epithelium of chorioallantoic placenta in both species is further ridged, forming a knobbly uterine surface. The ultrastructural evidence between N. metallicus and N. ocellatus cannot strictly account for the distinct differences in their placentotrophy; as yet unexplored molecular nutrient transport mechanisms that are not reflected in uterine ultrastructure must play significant roles in nutrient transportation. Characteristics consistent with a plasma membrane transformation were confirmed in both species. [ABSTRACT FROM AUTHOR]

The article offers information on a study that examines the umbilical vein blood flow (UVBF) during the first trimester in pregnancies with low serum pregnancy-associated plasma protein-A (PAPP-A) levels relative to the development of fetal intrauterine growth restriction (IUGR). The study performed a UVBF assessment at 11+0 to 13+6 weeks' gestation in 102 singleton pregnancies. It shows that a decreased in UV-TAMXV and UVBF identify fetuses at high risk of developing among pregnancies IUGR.