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Introduction: Our objective was to evaluate the efficacy of expanded non‐invasive prenatal testing (NIPT) that includes both trisomies and copy number variants (CNVs) in high‐risk twin pregnancies. Material and Methods: A prospective, double‐blinded cohort study was conducted, enrolling 73 high‐risk twin pregnancies characterized by increased risk of genetic disorders due to factors such as increased nuchal translucency, structural anomalies, fetal growth restriction, and other factors associated with chromosomal abnormality. Participants underwent invasive karyotyping and chromosomal microarray analysis, alongside separate expanded NIPT for research purposes. The sensitivity, specificity, positive predictive value, and negative predictive value of expanded NIPT were calculated. Results: The cohort included 24 monochorionic and 49 dichorionic twin pregnancies. The median cell‐free fetal DNA concentration in expanded NIPT was 16.7% (range 3.86%–49.1%), with a test failure rate of 1.4% (1/73). High‐risk findings for trisomy 21/13/18 were identified in five cases (6.8%), Turner syndrome in one case (1.4%), and CNVs indicative of high risk for clinically significant microdeletion/microduplication syndromes (MMS) in ten cases (13.7%). Of these, 56 cases (76.7%) tested NIPT negative, revealing one false‐negative for 45, X and five false‐negatives for CNVs. Expanded NIPT achieved a detection rate of 100% (5/5) for trisomy 21/13/18 with a false‐positive rate of 0% (0/5), a detection rate of 33.3% (1/3) for sex chromosome abnormalities with a false‐positive rate of 0% (0/3), and a detection rate of 66.7% (4/6) for MMS with a false‐positive rate of 3.0% (2/67). The positive predictive values for trisomy T21/13/18, sex chromosome abnormalities, and known MMS were 100% (5/5), 100% (1/1), and 66.7% (4/6) in the expanded NIPT, respectively. Conclusions: The expanded NIPT demonstrated high detection rates for common trisomies and moderate detection rates for prenatal MMS in high‐risk twin pregnancies. Further studies with large sample sizes in low‐risk populations are needed. [ABSTRACT FROM AUTHOR]

To investigate the risk factors influencing very early preterm and early preterm births in twin pregnancies after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). This retrospective study analyzed 2042 twin pregnancies that underwent embryo transfer via IVF/ICSI at the Reproductive Center of Sir Run Run Shaw Hospital between January 2019 and December 2022. Spontaneous very early, early preterm, and provider‐initiated preterm births were examined separately. Based on gestational age, participants were categorized into three groups: very early preterm birth (<28 weeks), early preterm birth (≥28 to <34 weeks), and ongoing pregnancy (≥34 weeks). Univariate analysis was conducted to assess general conditions, among the three groups. Multiple logistic regression analysis was performed to identify independent risk factors for very early and early spontaneous preterm birth in twin pregnancies. A total of 2042 twin pregnancies were included in the study, with birth rates of 4.36% (89 of 2042) <28 weeks, 12.14% (248 of 2042) ≥28 to <34 weeks, and 83.50% (1705 of 2042) ≥34 weeks. The primary cause of provider‐initiated preterm birth <28 weeks was placental factors, while hypertensive disorders of pregnancy (31.11%) were the predominant cause for preterm births ≥28 to <34 weeks. Multiple logistic regression analysis identified the independent risk factors for births <28 weeks (P < 0.05) as cervical cerclage, history of late miscarriage or premature birth, uterine adhesions, primary infertility of polycystic ovary syndrome (PCOS), monochorionic pregnancies, history of cervical surgery, uterine malformations, body mass index ≥25 kg/m2, and uterine longitudinal axis lengths <3.6 cm. Cervical cerclage, main factors of infertility (PCOS), adenomyosis, and uterine longitudinal axis lengths <3.6 cm were identified as independent risk factors for ≥28 to 34 weeks (P < 0.05). It is crucial to consider risk factors during IVF/ICSI treatment because of the high incidence of very early and early preterm twin pregnancies, which can be identified early and properly managed. [ABSTRACT FROM AUTHOR]

Objective: To determine the association of first‐trimester uterine artery Doppler with hypertensive disorders of pregnancy in twin pregnancies. Methods: This was a retrospective cohort study of twin pregnancies followed at the University Hospital Center of Central Lisbon, Portugal, between January 2010 and December 2022. First‐trimester uterine artery pulsatility index (UtA‐PI) was determined and compared between twin pregnancies (n = 454) and singleton pregnancies (n = 908), matched to maternal and pregnancy characteristics. Maternal characteristics and mean UtA‐PI were analyzed for gestational age, birth weight, gestational hypertension, early‐ and late‐onset pre‐eclampsia, HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome, and preterm birth. Univariable and multivariable logistic regression models were used. Results: The mean first‐trimester UtA‐PI was significantly lower in dichorionic twins than in singletons (P < 0.001). To study hypertensive disorders of pregnancy in twins, 390 pregnancies were included: 311 (79.7%) dichorionic and 79 (20.3%) monochorionic twins. The observed rates of early‐ and late‐onset pre‐eclampsia, gestational hypertension, and HELLP syndrome were 1.0%, 4.4%, 7.4%, and 1.5%, respectively. We achieved a 100% detection rate for early‐onset pre‐eclampsia using the UtA‐PI 90th centile for twins. However, when singleton references were considered, the detection rate decreased to 50%. UtA‐PI at or above the 95th centile was associated with increased odds for preterm birth before 32 weeks (adjusted odds ratio 4.1, 95% confidence interval 1.0–16.7, P = 0.043). Conclusions: Unless other major risk factors for hypertensive disorders are present, women with low UtA‐PI will probably not benefit from aspirin prophylaxis. Close monitoring of all twin pregnancies for hypertensive disorders is still recommended. Synopsis: A first‐trimester uterine artery pulsatility index above the 90th centile, considered for twin pregnancies, detected all cases of early‐onset pre‐eclampsia. [ABSTRACT FROM AUTHOR]

The accurate assessment of wound healing post‐caesarean section, especially in twin pregnancies, remains a pivotal concern in obstetrics, given its implications for maternal health and recovery. Traditional methods, including conventional abdominal ultrasonography (CU), have been challenged by the advent of transvaginal ultrasonography (TU), offering potentially enhanced sensitivity and specificity. This meta‐analysis directly compares the efficacy of TU and CU in evaluating wound healing and scar formation, crucial for optimizing postoperative care. Results indicate that TU is associated with significantly better outcomes in wound healing, demonstrated by lower REEDA scores (SMD = −20.56, 95% CI: [−27.34.20, −13.77], p < 0.01), and in scar formation reduction, evidenced by lower Manchester Scar Scale scores (SMD = −25.18, 95% CI: [−29.98, −20.39], p < 0.01). These findings underscore the potential of integrating TU into routine post‐caesarean evaluation protocols to enhance care quality and patient recovery. [ABSTRACT FROM AUTHOR]

Objective: Most of the published literature on selective fetal growth restriction (sFGR) has focused on monochorionic twin pregnancies. The aim of this systematic review was to report on the outcome of dichorionic diamniotic (DCDA) twin pregnancies complicated by sFGR. Methods: MEDLINE, EMBASE and The Cochrane Library databases were searched. The inclusion criteria were DCDA twin pregnancies complicated by sFGR. The outcomes explored were intrauterine death (IUD), neonatal death and perinatal death (PND), survival of at least one and both twins, preterm birth (PTB) (either spontaneous or iatrogenic) prior to 37, 34, 32 and 28 weeks' gestation, pre‐eclampsia (PE) or gestational hypertension, neurological, respiratory and infectious morbidity, Apgar score < 7 at 5 min, necrotizing enterocolitis, retinopathy of prematurity and admission to the neonatal intensive care unit (NICU). A composite outcome of neonatal morbidity, defined as the occurrence of respiratory, neurological or infectious morbidity, was also evaluated. Random‐effects meta‐analysis was used to analyze the data, and results are reported as pooled proportion or odds ratio (OR) with 95% CI. Results: Thirteen studies reporting on 1339 pregnancies with sFGR and 6316 pregnancies without sFGR were included. IUD occurred in 2.6% (95% CI, 1.1–4.7%) of fetuses from DCDA pregnancies with sFGR and 0.6% (95% CI, 0.3–9.7%) of those from DCDA pregnancies without sFGR, while the respective values for PND were 5.2% (95% CI, 3.5–7.3%) and 1.7% (95% CI, 0.1–5.7%). Spontaneous or iatrogenic PTB before 37 weeks complicated 84.1% (95% CI, 55.6–99.2%) of pregnancies with sFGR and 69.1% (95% CI, 45.4–88.4%) of those without sFGR. The respective values for PTB before 34, 32 and 28 weeks were 18.4% (95% CI, 4.4–38.9%), 13.0% (95% CI, 9.5–17.1%) and 1.5% (95% CI, 0.6–2.3%) in pregnancies with sFGR and 10.2% (95% CI, 3.1–20.7%), 7.8% (95% CI, 6.8–9.0%) and 1.8% (95% CI, 1.3–2.4%) in those without sFGR. PE or gestational hypertension complicated 19.9% (95% CI, 12.4–28.6%) of pregnancies with sFGR and 12.8% (95% CI, 10.4–15.4%) of those without sFGR. Composite morbidity occurred in 28.2% (95% CI, 7.8–55.1%) of fetuses from pregnancies with sFGR and 13.9% (95% CI, 6.5–23.5%) of those from pregnancies without sFGR. When stratified according to the sFGR status within a twin pair, composite morbidity occurred in 39.0% (95% CI, 11.1–71.5%) of growth‐restricted fetuses and 29.9% (95% CI, 3.5–65.0%) of appropriately grown fetuses (OR, 1.9 (95% CI, 1.7–3.1)), while the respective values for PND were 3.0% (95% CI, 1.8–4.5%) and 1.6% (95% CI, 0.9–2.6%) (OR, 2.1 (95% CI, 1.0–4.1)). On risk analysis, DCDA pregnancies complicated by sFGR had a significantly higher risk of IUD (OR, 5.2 (95% CI, 3.2–8.6)) and composite morbidity or admission to the NICU (OR, 3.2 (95% CI, 1.9–5.6)) compared to those without sFGR, while there was no difference in the risk of PTB before 34 weeks (P = 0.220) or PE/gestational hypertension (P = 0.210). Conclusions: DCDA twin pregnancies complicated by sFGR are at high risk of perinatal morbidity and mortality. The findings of this systematic review are relevant for counseling and management of complicated DCDA twin pregnancies, in which twin‐specific, rather than singleton, outcome data should be used. © 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: To compare the maternal and neonatal outcomes of twin pregnancies between vertex and nonvertex presentations of the second twin in vaginal delivery. Methods: In this unicentric retrospective cohort study, we collected data from 213 cases of vaginal twin deliveries from January 2016 to July 2020. Participants were divided into the vertex‐vertex presentation group (VV) and vertex‐breech presentation group (VB). Data on maternal and neonatal outcomes were compared between groups. Results: Among the 213 mothers and 426 infants (213 twin pairs), there were 140 women in the VV group and 73 women in the VB group (65.73% vs. 34.27%). Infants in the VB group had a higher incidence of admission to NICU (51.43% vs. 68.49%, p = 0.017), lower 1‐min (11.43% vs. 28.77%, p < 0.001) and 5‐minute Apgar scores (1.43% vs. 4.11%, p = 0.043) for the second twin. However, after the adjustment for sex of the twin, birth weight, chorionicity, and gestational age, the greater risk of admission to NICU and low 5‐min Apgar score was no longer significantly different. Conclusion: VB twins are at no greater overall risk of a poor outcome due to breech presentation in the second twin. However, the presentation of the second fetus represents a risk factor for a low 1‐min Apgar score. Obstetricians and midwives should consider appropriate interventions for second twins who present breech versus vertex. [ABSTRACT FROM AUTHOR]

Background: The purpose of this project was to investigate the relationship between prepregnancy body mass index (ppBMI), gestational weight gain (GWG), and pregnancy outcomes in women with twin pregnancies. Methods: A prospective cohort of 369 women with dichorionic diamniotic twin pregnancies was recruited from 2016 to 2020. According to ppBMI using Chinese BMI classifications, they were categorized into the underweight (BMI < 18.5 kg/m2), normal (BMI 18.5–23.9 kg/m2), and overweight and obese (BMI ≥ 24 kg/m2) groups. In each ppBMI group, they were divided into two subgroups based on the presence or absence of the complications such as gestational diabetes mellitus (GDM), hypertensive disorders of pregnancy (HDP), and small for gestational age (SGA). The outcomes including GDM, HDP, and SGA were compared among three ppBMI groups, and the associations of GWG with these outcomes within each ppBMI category were analyzed. Results: Twin‐pregnant women with overweight and obesity were at increased risks of HDP (aOR = 4.417 [95% CI = 1.826–9.415]) and SGA (2.288 [1.102–4.751]), whereas underweight women were prone to deliver SGA newborns (2.466 [1.157–5.254]). Women with GDM gained less weight during pregnancy than those without GDM within each ppBMI category. For overweight and obese women, greater GWG increased the incidence of HDP (1.235 [1.016–1.500]) and decreased the risk of SGA (0.818 [0.702–0.953]). Conclusions: Both ppBMI and GWG in twin‐pregnant women were strongly associated with HDP and SGA, but not GDM. [ABSTRACT FROM AUTHOR]

Introduction: Cervical cerclage is controversial in twin pregnancies, although recent data from the USA supports its use where "physical examination‐indicated". Limited data exist, however, in the extreme situation of 0‐mm ultrasound‐measured cervical length or even prolapsed membranes. This research compares the success of emergency cervical cerclage in multiple and singleton pregnancies. Material and methods: This is a retrospective cohort study of all such cerclages performed at a tertiary hospital over a 15‐year period. "Emergency" was where transvaginal ultrasound‐assessed cervical length was 0 mm, with amniotic membranes at or beyond the external cervical os. Exclusion criteria were clinical or biochemical evidence of infection, regular contractions, bleeding, ruptured membranes, or gestation beyond 24+0 weeks. The primary outcome, or "success", was defined as birth >27+6 weeks of gestation, with the neonate alive 28 days later with no markers of adverse outcome (seizures, periventricular leukomalacia, intracranial hemorrhage more than Grade 2, or necrotizing enterocolitis). Demographic and cerclage variables were assessed against the primary outcome. Variables correlated with success were analyzed between multiple and singleton pregnancies. Comparison of all adverse outcomes was then adjusted using logistic regression. Results: A total of 135 pregnancies were included (107 singletons and 28 multiples [all twins]). Success was achieved in 79 (58.5%; 57.9% in singletons, 60.7% in twins). Nulliparity, in utero transfer, symptoms, prolapsed membranes, and dilation more than 3 cm were predictors of failure, but twin pregnancy was not. After controlling for potential confounding variables, there was no significant difference in measures of success between singleton and twin pregnancies, apart from higher rates of neonatal unit admission. Conclusions: Emergency cervical cerclage, even in extreme situations, is as effective in twin pregnancies as it is in singletons. [ABSTRACT FROM AUTHOR]

Objectives: The primary aim was to measure uterine artery (UtA) indices in twin pregnancies of Polish Caucasian women and compare it with a previously published study by Geipel et al for DC twins (2011). The secondary aim was to find differences in UtA indices in MC, DC twins, and singletons. Methods: A prospective longitudinal evaluation of UtA Doppler indices in 1462 examinations of twins and 5766 examinations of singletons between 17 and 37 gestational age (GA). Pulsatility index (PI) and resistance index (RI) were calculated. Results: UtA PI and RI are lower in the twins than singletons but the analyzed mean values throughout gestation are higher than the study presented by Geipel et al. Obtained curves for DC twins and singletons had the same form as Geipel's curves. In MC twins, curves are flatter and characterized by lower differences throughout pregnancy than Geipel's curves for DC twins. They tend to be more similar about 32 weeks of gestations, resulting from different placenta structure in MC than DC twin pregnancies. Conclusions: UtA Doppler indices in twin pregnancies are lower than in singletons. Obtained data have higher values for twins than reference charts proposed by Geipel's for dichorionic twins. We observed some differences between monochorionic and dichorionic twins' curves throughout pregnancy, but they were not significant. [ABSTRACT FROM AUTHOR]

Introduction: The effects of assisted reproductive technology on the outcomes of twin pregnancies are controversial. Therefore, the purpose of this study was to compare the maternal and perinatal outcomes of twin pregnancies conceived spontaneously and those conceived by assisted reproductive technology.Material and Methods: This was a cross-sectional study performed at Peking Union Medical College Hospital (PUMCH). Data on twin pregnancies (conceived spontaneously and by in vitro fertilization [IVF]/intracytoplasmic sperm injection [ICSI]) were obtained from the National Birth Registry of China for the period between 1 October 2016, and 30 September 2017. The primary obstetric outcomes were compared between twin pregnancies conceived by different methods. Logistic regression analysis with 95% confidence intervals (95% CI) was used for the multivariate analysis.Results: A total of 3270 twin pregnancies (2003 and 1209 conceived spontaneously and by IVF/ICSI, respectively) were identified. The proportion of twin pregnancies among all pregnancies was 3.4% (3332/97 278). Multiple regression analysis indicated that the incidences of gestational diabetes mellitus (adjusted odds ratio [AOR] = 1.42, 95% CI 1.10-1.83, p = 0.007), preterm premature rupture of membranes (AOR = 1.65, 95% CI 1.21-2.25, p = 0.002), placenta accreta spectrum (AOR = 2.12, 95% CI 1.42-3.17, p < 0.001) and postpartum hemorrhage (AOR = 1.38, 95% CI 1.02-1.86, p = 0.037) were significantly higher in the IVF/ICSI group than in the natural pregnancy group. Multivariate analysis also revealed that conception mode was not an independent risk factor for neonate outcomes.Conclusions: In twin pregnancies, IVF/ICSI is independently associated with multiple maternal complications, including gestational diabetes mellitus, preterm premature rupture of membranes and placenta accreta spectrum compared with spontaneous conception, although potential residual confounders due to indications for assisted reproductive technology exist. [ABSTRACT FROM AUTHOR]

Background: Preterm birth is a major cause of perinatal morbidity and mortality worldwide. In many countries, the preterm birth rate in women with a multiple pregnancy is increasing, mostly due to an increase in iatrogenic preterm birth. Aims: To investigate trends in preterm birth in twin pregnancies in Victoria, Australia, in relation to maternal and perinatal complications. Materials and methods: We conducted a retrospective population‐based cohort study in all women with a twin pregnancy who delivered at or after 20 weeks of gestation in the state of Victoria, Australia between 2007 and 2017. Annual spontaneous and iatrogenic preterm birth rates were calculated and trends analysed. Incidence of adverse pregnancy outcomes, maternal complications and risk factors for preterm birth were analysed. Results: We studied 12 757 women with a twin pregnancy. Between 2007 and 2017 the preterm birth rate increased from 641/1231 (52%) to 803/1158 (69%), mainly due to an increase in iatrogenic preterm birth from 342/1231 (28%) to 567/1158 (49%). This was irrespective of the presence of pregnancy complications. Our study showed neither a decrease in perinatal mortality from 28 weeks of gestation nor in preterm average weekly prospective stillbirth risk. Conclusion: Preterm birth rates in twins in Victoria are increasing, mainly driven by an increase in iatrogenic preterm birth. This occurred both in complicated and non‐complicated twin pregnancies, and has not been accompanied by reduction in perinatal mortality from 28 weeks. [ABSTRACT FROM AUTHOR]

Introduction: Preeclampsia affects about 10% of twin pregnancies and significantly increases the risk of adverse pregnancy outcomes. However, screening models for preeclampsia in twin pregnancies remain elusive. The present study aimed to evaluate the performance of a multi-marker first trimester preeclampsia screening model in low-risk twin pregnancies.Material and Methods: Between 2014 and 2017, we prospectively assessed first trimester biomarkers for preeclampsia in a 'low-risk' twin pregnancy cohort at a single center. Multiple logistic regression was used to determine significant predictors for early preeclampsia (occurring prior to 34 weeks) and late preeclampsia (occurring after 34 weeks). The performance of the screening models fitted using the significant predictors was calculated using receiver operating characteristics curves, and internal validation was performed using bootstrapping.Results: A total of 769 twin pregnancies were included in the study. Early preeclampsia and late preeclampsia developed in 27 (3.5%) and 59 (7.7%) cases, respectively. Logistic regression analyses showed that maternal age, body mass index, mean artery pressure and placental growth factor were significant predictors for early preeclampsia. Maternal age, body mass index, mean artery pressure and pregnancy-associated plasma protein A were significant for late preeclampsia. Uterine artery pulsatility index was not predictive of either early or late preeclampsia. For the fitted screening model of early and late preeclampsia, the areas under receiver operating characteristics curves were 0.82 (95% confidence interval [CI] 0.76-0.88) and 0.66 (95% CI 0.59-0.73), which were expected to decrease to 0.77 and 0.60, respectively, based on bootstrapping; the positive predictive values were 10.2% and 12.5%; and the estimated detection rates were 40.7% and 22.0%, respectively, at a false-positive rate of 10%.Conclusions: A multi-marker screening model for preeclampsia in low-risk twin pregnancies, using a modified version of Fetal Medicine Foundation predictors in singletons, does not perform well. Uterine artery pulsatility index is of little value in screening for preeclampsia in low-risk twin pregnancies. [ABSTRACT FROM AUTHOR]

Introduction: The objective of this study was to report on the clinical performance of non-invasive prenatal testing (NIPT) for trisomies 21, 18 and 13 in twin pregnancies and to define the performance of NIPT by combining our cohort study results with published studies in a systematic meta-analysis.Material and Methods: A cohort study was carried out in the First Affiliated Hospital of Sun Yat-sen University and Kanghua Hospital. Meanwhile, searches of PubMed, EMBASE, The Cochrane Library and Web of Science for all relevant peer-reviewed articles were performed with a restriction to English language publication before 15 June 2019. Quality assessments were conducted with the Quality Assessment Tool for Diagnostic Accuracy Studies-2 checklist. Data analysis, heterogeneity, subgroup analysis and publication bias were carried out using META-DISC 1.4 and STATA 12.0.Results: In all, 141 twin pregnancies included in our cohort study; confirmation revealed one true-positive case for trisomy 21 and 140 true-negative cases. The sensitivity and specificity for trisomy 21 by NIPT were both 100%. Twenty-two eligible studies were enrolled in this meta-analysis together with our study. There were 199 cases of trisomy 21, 58 cases of trisomy 18, 14 cases of trisomy 13 and 6347 cases of euploids in total. For trisomy 21, NIPT showed the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 0.99, 1.00, 145.81, 0.06 and 1714.09, respectively. For trisomy 18, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 0.88, 1.00, 200.98, 0.19 and 483.68, respectively.Conclusions: The performance of NIPT for trisomy 21 in twin pregnancy was excellent and it was similar to that reported in singleton pregnancy. However, due to publication bias (trisomy 18) and small number of cases (trisomy 13), accurate assessment of the predictive performance of NIPT for trisomies 18 and 13 could not be achieved. [ABSTRACT FROM AUTHOR]

Objectives: To explore the outcome of monochorionic monoamniotic (MCMA) twin pregnancies affected by twin-to-twin transfusion syndrome (TTTS).Methods: MEDLINE and EMBASE databases were searched for studies reporting the outcome of MCMA twin pregnancies complicated by TTTS. The primary outcome was intrauterine death (IUD); secondary outcomes were miscarriage, single IUD, double IUD, neonatal death (NND), perinatal death (PND), survival of at least one twin, survival of both twins and preterm birth (PTB) before 32 weeks' gestation. Outcomes were assessed in MCMA twins affected by TTTS not undergoing intervention and in those treated with amniodrainage, laser therapy or cord occlusion. Subgroup analysis was performed including cases diagnosed before 24 weeks. Random-effects meta-analysis of proportions was used to analyze the data.Results: Fifteen cohort studies, including 888 MCMA twin pregnancies, of which 44 were affected by TTTS, were included in the review. There was no randomized trial comparing the different management options in MCMA twin pregnancies complicated by TTTS. In cases not undergoing intervention, miscarriage occurred in 11.0% of fetuses, while the incidence of IUD, NND and PND was 25.2%, 12.2% and 31.2%, respectively. PTB complicated 50.5% of these pregnancies. In cases treated by laser surgery, the incidence of miscarriage, IUD, NND and PND was 19.6%, 27.4%, 7.4% and 35.9%, respectively, and the incidence of PTB before 32 weeks' gestation was 64.9%. In cases treated with amniodrainage, the incidence of IUD, NND and PND was 31.3%, 13.5% and 45.7% respectively, and PTB complicated 76.2% of these pregnancies. Analysis of cases undergoing cord occlusion was affected by the very small number of included cases. Miscarriage occurred in 19.2%, while there was no case of IUD or NND of the surviving twin. PTB before 32 weeks occurred in 50.0% of these cases.Conclusions: MCMA twin pregnancies complicated by TTTS are at high risk of perinatal mortality and PTB. Further studies are needed in order to elucidate the optimal type of prenatal treatment in these pregnancies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this systematic review was to quantify the association between birthweight discordance and neonatal morbidity in twin pregnancies.Material and Methods: MEDLINE, Embase and Cinahl databases were searched. Studies reporting the occurrence of morbidity in twins affected compared with those not affected by birthweight discordance were included. The primary outcome was composite neonatal morbidity (including neurological, respiratory, infectious morbidities, abnormal acid-base status and necrotizing enterocolitis). The secondary outcomes were the individual morbidities. Sub-group analysis according to chorionicity, gestational age at birth and fetal weight (smaller vs larger twin) was also performed. Random-effect head-to-head meta-analyses were used to analyze the data.Results: Twenty studies (10 851 twin pregnancies) were included. The risk of composite morbidity was significantly higher in the pregnancies with birthweight discordance ≥15% (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.0-1.9), ≥20% (OR 2.2, 95% CI 1.40-3.45), ≥25% (OR 2.5, 95% CI 1.8-3.6), and ≥30% (OR 3.4, 95% CI 2.2-3.2). In dichorionic twins, birthweight discordance ≥15% (OR 2.4, 95% CI 1.65-3.46), ≥20% (OR 2.2, 95% CI 1.3-3.8), ≥25% (OR 2.7, 95% CI 1.4-5.1) and ≥30% (OR 3.6, 95% CI 2.3-5.7) were all significantly associated with composite neonatal morbidity. Analysis of monochorionic twins was hampered by the very small number of included studies, which precluded adequate statistical power. Monochorionic twins with a birthweight discordance ≥20% were at significantly higher risk of composite neonatal morbidity (OR 2.2, 95% CI 1.1-4.9) compared with those presenting with lesser degree of discordance. When stratifying the analysis according to gestational age at birth and fetal size, twins with birthweight discordance ≥15%, 20%, 25% and 30% delivered at ≥34 weeks were at higher risk of neonatal morbidity compared with controls, but there was no difference in the risk of morbidity between the larger and the smaller twin in the discordant pair.Conclusions: Birthweight discordance is associated with neonatal morbidity in twin pregnancies. The strength of this association persists for dichorionic twins. It was not possible to extrapolate robust evidence on monochorionic twins due to the low power of the analysis due to the small number of included studies. [ABSTRACT FROM AUTHOR]

Objective: To examine the association between inter‐twin delivery interval and short‐term perinatal outcomes of the second twin after vaginal delivery of the first twin. Methods: Retrospective cohort study including twin pregnancies with a vaginal delivery of the first twin between January 2011 and September 2017 in a tertiary hospital in Melbourne, Australia. The main outcome measure was a composite of adverse neonatal outcome (at least one of perinatal death, admission to neonatal intensive care unit (NICU), endotracheal intubation, Apgar <7 at five minutes and cord lactate >4.0 mmol/L). Proportions of adverse outcomes for the second twin were compared between groups of intervals ≤ or >10 and ≤ or >30 min. Results: The composite adverse neonatal outcome occurred in 201 (58.2%) and a caesarean section occurred in seven cases (2%) of the 345 pregnancies included. Delivery interval was associated with higher cord lactate. Low Apgar scores were more frequent with intervals >30 min (17.9% vs 6.6%, P = 0.03), as well as caesarean section for the second twin (10.7% vs 1.3%, P = 0.01). Composite adverse outcome and admission to NICU were not significantly influenced by the delivery interval. Predictors of adverse outcome were gestational age, abnormal cardiotocography and breech delivery of the second twin. Conclusion: The inter‐twin delivery interval is associated with higher rates of low Apgar scores and higher cord lactate for the second twin. These associations do not translate into higher rates of admission to NICU and their long‐term clinical implications are uncertain. [ABSTRACT FROM AUTHOR]

The rate of twinning is rising and since the introduction of non-invasive prenatal testing, interest in and uptake of genetic screening and testing in twin pregnancies has not been investigated. This study aimed to explore the attitudes toward and uptake of current prenatal genetic screening and diagnostic testing options for fetal aneuploidy in twin pregnancies. Women being seen for genetic counseling with twin gestations were recruited for participation in a descriptive study with questionnaire (n = 42) and semi-structured phone interview (n = 15). Women were significantly more in favor of screening than diagnostic testing (p = 0.049). Sixty-nine (n = 25) percent elected screening, while one participant had a diagnostic procedure. Women were interested in screening for preparation or reassurance despite having concerns about accuracy and uncertainty. Most women (86%) felt they would make the same decision in a singleton pregnancy. Despite this, 48% cited twin pregnancy as influential to some degree. Information learned from providers, past experiences, and family and friends were also cited as influencing and anchoring factors, suggesting that tailoring prenatal genetic counseling sessions for twins might parallel that of singletons. No significant differences between natural and assisted conception patients were found. Although it did not alter patient decisions, genetic counseling was used as a platform to raise concerns and gather information. [ABSTRACT FROM AUTHOR]

Objectives: The primary aim of this systematic review was to explore the strength of association between birth-weight (BW) discordance and perinatal mortality in twin pregnancy. The secondary aim was to ascertain the contribution of gestational age and growth restriction in predicting mortality in growth-discordant twins.Methods: MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases were searched. Only studies reporting on the risk of mortality in twin pregnancies affected compared with those not affected by BW discordance were included. The primary outcomes explored were incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death. Outcome was assessed separately for monochorionic (MC) and dichorionic (DC) twin pregnancies. Analyses were stratified according to BW discordance cut-off (≥ 15%, ≥ 20%, ≥ 25% and ≥ 30%) and selected gestational characteristics, including incidence of IUD or NND before and after 34 weeks' gestation, presence of at least one small-for-gestational age (SGA) fetus in the twin pair and both twins being appropriate-for-gestational age. Risk of mortality in the larger vs smaller twin was also assessed. Meta-analyses using individual data random-effects logistic regression and meta-analyses of proportion were used to analyze the data.Results: Twenty-two studies (10 877 twin pregnancies) were included in the analysis. In DC pregnancies, a higher risk of IUD, but not of NND, was observed in twins with BW discordance ≥ 15% (odds ratio (OR) 9.8, 95% CI, 3.9-29.4), ≥ 20% (OR 7.0, 95% CI, 4.15-11.8), ≥ 25% (OR 17.4, 95% CI, 8.3-36.7) and ≥ 30% (OR 22.9, 95% CI, 10.2-51.6) compared with those without weight discordance. For each cut-off of BW discordance explored in DC pregnancies, the smaller twin was at higher risk of mortality compared with the larger one. In MC twin pregnancies, excluding cases affected by twin-twin transfusion syndrome, twins with BW discordance ≥ 20% (OR 2.8, 95% CI, 1.3-5.8) or ≥ 25% (OR 3.2, 95% CI, 1.5-6.7) were at higher risk of IUD, compared with controls. MC pregnancies with ≥ 25% weight discordance were also at increased risk of NND (OR 4.66, 95% CI, 1.8-12.4) compared with those with concordant weight. The risk of IUD was higher when considering discordant pregnancies involving at least one SGA fetus. The overall risk of mortality in MC pregnancies was similar between the smaller and larger twin, except in those with BW discordance ≥ 20%.Conclusion: DC and MC twin pregnancies discordant for fetal growth are at higher risk of IUD but not of NND compared with pregnancies with concordant BW. The risk of IUD in BW-discordant DC and MC twins is higher when at least one fetus is SGA. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Objective: To examine potential associations between the presence of fibroids and obstetric outcomes in twin pregnancies.Methods: A prospective cohort study compared obstetric outcomes between individuals with twin pregnancies who did and did not have fibroids. Patients were considered for inclusion if they underwent first-trimester ultrasonography examination, and went on to deliver at the Beijing Obstetrics and Gynecology Hospital between September 1, 2012 and December 31, 2014. Participants were grouped based on the presence or absence of fibroids and baseline demographics, fibroid characteristics, and obstetric outcomes were recorded and compared between the two groups.Results: In total, 153 patients with twin pregnancies were recruited; 51 had fibroids and 102 did not. Patients in the fibroid group demonstrated a higher maternal age (P<0.001), higher pre-pregnancy body mass index (P=0.01), and higher rate of assisted reproductive technology use (P=0.04). The presence of fibroids was not associated with any change in obstetric outcomes, and obstetric outcomes were unaffected by the number, size, location, and type of fibroids (all P>0.05).Conclusion: Fibroids were not a risk factor for any adverse obstetric outcomes among patients with twin pregnancies. [ABSTRACT FROM AUTHOR]

Objective The aim of this study was to determine the association between biometry discordance at the time of the anomaly scan and adverse perinatal outcomes in twin pregnancies. Design Retrospective cohort study. Setting Nine hospitals in the Southwest Thames Region of London Obstetric Research Collaborative ( STORK). Population or sample Population multicentre retrospective study of all twin pregnancies booked for antenatal care in nine hospitals over a period of 10 years. Methods Logistic regression and receiver operating characteristic ( ROC) curve analyses were performed to evaluate the association between abdominal circumference ( AC) and estimated fetal weight ( EFW) discordance, recorded between 20 and 22 weeks of gestation, and adverse pregnancy outcomes. Main outcome measures Stillbirth, neonatal mortality, preterm birth ( PTB) at <34 weeks of gestation, and birthweight ( BW) discordance ≥25%. Results A total of 2399 twin pregnancies [457 monochorionic ( MC) and 1942 dichorionic ( DC)] were included in the study. The predictive accuracy of the EFW discordance was poor for fetal loss after 22 weeks of gestation (area under the curve, AUC 0.54, 95% CI 0.46-0.64), fetal loss beyond 28 weeks of gestation ( AUC 0.42, 95% CI 0.31-0.52), perinatal loss ( AUC 0.51, 95% CI 0.44-0.57), BW discordance ( AUC 0.63, 95% CI 0.56-0.65), and PTB before 34 weeks of gestation ( AUC 0.52, 95% CI 0.49-0.55). There was no significant difference in the prediction of these outcomes when using EFW discordance or AC discordance. Conclusions Once structural malformations, chromosomal abnormalities, and twin-to-twin transfusion syndrome have been excluded, second-trimester EFW and AC discordance have poor predictive value for adverse perinatal outcomes in twin pregnancy. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Evidence for the role of first-trimester ultrasound in predicting outcome in twin pregnancies is conflicting. The aim of this study was to determine the association between crown-rump length ( CRL) discordance and adverse perinatal outcome in twin pregnancies. Methods This was a retrospective study of all twin pregnancies of known chorionicity from a large regional cohort over a 10-year period. Terminations of pregnancy, cases with fetal or chromosomal abnormalities and monoamniotic pregnancies were excluded. Receiver-operating characteristics ( ROC) curve and logistic regression analyses were performed to evaluate the association between CRL discordance and stillbirth, neonatal mortality, intrauterine growth restriction, preterm birth ( PTB) at < 34 weeks' gestation and birth weight ( BW) and ultrasound estimated fetal weight ( EFW) discordance of ≥ 25%. Results A total of 2155 twin pregnancies were analyzed, of which 420 were monochorionic ( MC) and 1735 dichorionic ( DC). There were 42 fetal losses before 24 weeks' gestation and 23 perinatal deaths. CRL discordance was poorly predictive for fetal loss at < 24 weeks (area under the ROC curve ( AUC), 0.54 (95% CI, 0.46-0.62)), perinatal loss ( AUC, 0.52 (95% CI, 0.41-0.64)), BW discordance ( AUC, 0.61 (95% CI, 0.56-0.65)), BW < 5th centile ( AUC, 0.56 (95% CI, 0.53-0.59)), EFW discordance ( AUC, 0.55 (95% CI, 0.51-0.60)) and PTB at < 34 weeks ( AUC, 0.50 (95% CI, 0.47-0.54)). Overall mortality was significantly higher in MC (5.0%) than in DC (2.6%) twins ( P = 0.016). Logistic regression analysis demonstrated that chorionicity (odds ratio 2.09 (95% CI, 1.06-4.10); P = 0.033) independently contributed to determining mortality, while CRL discordance ( P = 0.201) did not. Adjusting for chorionicity did not improve the detection of adverse outcomes using CRL discordance. Conclusion In the absence of aneuploidy or structural fetal abnormality, CRL discordance is of poor predictive value for adverse perinatal outcome in both MC and DC twin pregnancies. CRL discordance should not be used routinely to identify twin pregnancies at high risk of adverse perinatal outcome. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Customized growth charts developed for singleton pregnancies have been shown to be more effective than population-based ones at identifying small-for-gestational age ( SGA) fetuses at risk for intrauterine fetal death ( IUFD). We sought to compare the association between SGA and IUFD in twins using customized growth charts designed for twin gestations compared to those designed for singletons. Methods This was a retrospective cohort study using a database including singleton and twin pregnancies undergoing ultrasound examination between 16 and 20 weeks' gestation. After excluding preterm births < 34 weeks, congenital anomalies and stillbirths, we identified 51 150 singleton births. Coefficients for significant physiological and pathological variables affecting birth weight for singletons were derived using backward stepwise multiple regression. The same process was repeated for twin births (1608 pairs), also adjusting for chorionicity. Customized growth charts for each pregnancy were derived using these two regression models for optimal birth weight at term and a proportionality equation. The association between SGA < 10th percentile, defined using the twin and singleton-customized charts, and IUFD were compared. Statistical analysis, including calculation of adjusted odds ratios ( OR) for IUFD and screening accuracy using each chart, was performed. Results The derived coefficients for optimal birth weight for twins were different from those for singletons, with lower constants and root mean square error (3422 and 288.9, respectively, in twins vs 3543 and 416 in singletons). Among 3786 twin infants, IUFD was seen in 123 (3.2%). The numbers of fetuses identified as SGA were 575 (15.2%) and 504 (13.3%) by the singleton and twin charts, respectively. Fetuses classified as SGA by the twin-specific customized charts were at a significantly increased risk for IUFD (adjusted OR, 2.3 (95% CI, 1.4-3.5)), whereas those classified as SGA by the singleton-customized charts were not (adjusted OR, 1.2 (95% CI, 0.7-2.0)). Conclusion Customized charts designed specifically for twins are more effective at identifying twin pregnancies at risk for IUFD than are those derived using singleton birth data. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Objective Studies on high-risk singleton gestations have shown a preventive effect of progesterone treatment on preterm delivery. This study was conducted to investigate the preventive effect of vaginal micronized progesterone in a large population of twin gestations. Methods This was a double-blind, placebo-controlled randomized trial performed in 17 centers in Denmark and Austria. Women with twin gestations were randomized to daily treatment with progesterone pessaries or apparently identical placebo pessaries, starting from 20-24 weeks until 34 weeks' gestation. Primary outcome was incidence of delivery before 34 weeks' gestation. Secondary outcomes were maternal and neonatal complications and long-term infant follow-up, by Ages and Stages Questionnaire (ASQ), 6 months and 18 months after the expected date of delivery. We also updated a published meta-analysis to include our data and those of another recently published twin trial. Results A total of 677 women were randomized to the two treatments. Two women in the placebo group were lost to follow-up. Baseline characteristics for the groups were similar. Incidence of delivery before 34 weeks was 15.3% in the progesterone group vs 18.5% in the placebo group (odds ratio, 0.8 (95% CI, 0.5-1.2)). Risks of maternal and neonatal complications were comparable for the two groups. Mean ASQ scores at 6 months and 18 months were not significantly different between the two groups (215 for infants in the progesterone group and 218 for infants in the placebo group at 6 months ( P = 0.45) and 193 and 194, respectively, at 18 months ( P = 0.89)). The meta-analysis gave a pooled odds ratio of 1.06 (95% CI, 0.86-1.31). Conclusion Progesterone treatment did not prevent preterm delivery in twin gestations. There were no harmful effects to fetuses and infants of maternal progesterone treatment. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Thrombin–antithrombin complex (TAT) is a sensitive marker for thrombin formation, and α2-plasmin inhibitor-plasmin complex (PIC) is a marker for fibrinolysis. Previous studies have shown that blood coagulation and fibrinolysis are activated in normal pregnancies. Thus, the present study examined changes in TAT and PIC levels during the course of singleton and twin pregnancies and compared these markers between the two pregnant groups. The subjects were 148 pregnant women, of whom 84 were women carrying single fetuses and 64 were women with twin fetuses. Their average gestational age at entry was 10, 20, 30 and 38 weeks of gestation in singleton pregnancies and 10, 20, 30 and 35 weeks in twin pregnancies. Peripheral blood was collected, and plasma was separated after centrifugation and then stored at −20 °C. The TAT levels increased significantly with the progression of pregnancy in both pregnant groups, whereas the PIC levels increased significantly only in singleton pregnancies between 30 and 38 weeks of gestation. The TAT levels were significantly higher in twin pregnancies than in singleton pregnancies. The PIC levels were significantly lower in twin pregnancies than in singleton pregnancies at 35–38 weeks. Thrombin formation might be enhanced with the progression of pregnancy in both pregnant groups. This enhancement might be more intensified in twin pregnancies. Fibrinolysis might increase only in singleton pregnancies from 30 to 38 weeks of gestation. Fibrinolysis might be less intensified in twin pregnancies than in singleton pregnancies only at 35–38 weeks. [ABSTRACT FROM AUTHOR]

Objective To study the outcome of 20 twin pregnancies with evidence of primary or recurrent cytomegalovirus (CMV) infection during pregnancy. Design Observational study. Setting Two tertiary perinatal departments in Israel. Population Twenty women with twin pregnancies who were referred because of serologic investigation indicating CMV infection. Seventeen women had evidence of primary CMV infection, and three women appeared to have recurrent CMV infection. Methods Prenatal diagnosis was made by amniocentesis of both sacs after 21 weeks of gestation. CMV isolation was performed by culture on fibroblasts, shell vial technique and polymerase chain reaction (PCR) amplification of CMV DNA. After birth, the neonatal urine and saliva were cultured for CMV. Main outcome measures Intrauterine CMV infection defined as positive PCR at amniotic fluid analysis and congenital CMV infection defined as positive CMV cultures after birth. Results Except for one, all women underwent amniocentesis of both gestational sacs. In 14 (70%) women, no evidence of vertical transmission to any of the 28 fetuses was found and none of the newborns had evidence of congenital CMV infection. Intrauterine infection was detected by amniocentesis in five women and by ultrasound findings with positive maternal serology in one. In three women, CMV was detected in only one amniotic sac. In five of our six total cases, both twins were found to have congenital CMV infection at birth, all of whom had dichorionic–diamniotic placentation, three fused and two separate. Conclusions In twin gestations, as in singletons, intrauterine and congenital CMV infection occurs in about 30% of women with primary or recurrent infection. The placenta type did not predict if one or both twins would be infected. Our data do not exclude the possibility that intrauterine transmission of the virus from one fetus to the other can occur. [ABSTRACT FROM AUTHOR]

There are conflicting data concerning perinatal outcome of twin,in vitrofertilization (IVF) pregnancies. The aim of this study was to evaluate and compare perinatal and neonatal outcomes in twin IVF pregnancies to those of spontaneously conceived twin gestations.The medical files of 73 IVF and 148 naturally conceived twin pregnancies were studied retrospectively. Data concerning maternal characteristics, obstetric complications, and neonatal outcome were recorded and compared byχ2 test. The one-way analysis of variance (anova) was used to compare the means of groups.Mean maternal age, the proportion of nulliparous women, and the incidence of premature rupture of membranes, cesarean section, and premature delivery were significantly higher in the study group. The mean birthweight was significantly lower, the frequency of admission to the intensive care unit and the duration of hospitalization were significantly higher in the study group. The incidence of intaventricular hemorrhage was significantly higher in the IVF group. The number of perinatal deaths was similar.IVF twin pregnancies are at greater risk for obstetric complications and adverse neonatal outcome in comparison with naturally conceived twin gestations. [ABSTRACT FROM AUTHOR]

Background: A twin pregnancy imposes greater demands on maternal physiology and smoking may thus be associated theoretically with a greater risk of preterm delivery than in singleton pregnancies.Population and Methods: From 1989 to 1996 all women who booked for antenatal care at the Department of Gynecology and Obstetrics, Aarhus University Hospital, Denmark were asked to fill in two questionnaires. Apart from smoking habits, these questionnaires provided information on medical and obstetric history together with information on sociodemographic and other lifestyle variables. Gestational age at delivery was calculated from ultrasonographically determined fetal biparietal diameter and information about the last menstrual period. Only women carrying twins were included in the present study (n=401).Results: Mean gestational age was 5 days (95% CI 1-9 days) shorter among smokers compared with non-smokers. Among non-smokers mean gestational age was 261 days (+/-18), among women who smoked 1-9 and 10+ cigarettes per day 257 days (+/-23) and 255 days (+/-20), respectively. The overall risk of preterm delivery (< 37 weeks) and delivery before 34 completed weeks was 1.3 (95% CI 0.9-2.2) and 1.4 (95% CI 0.8-2.4), respectively. Primiparous women had shorter gestational age than did multiparous women. Still, among primiparous as well as among multiparous women gestational age decreased with smoking. Adjustment for maternal age, height and prepregnancy weight, alcohol and caffeine intake, marital status, education, occupational status, preterm birth in previous pregnancies, and in vitro fertilization in the present pregnancy did not change the results.Conclusions: Smoking has a substantial effect on mean gestational age in twin pregnancies, and a dose response like relationship is present. [ABSTRACT FROM AUTHOR]