Vasa previa in singleton pregnancies: diagnosis and clinical management based on an international expert consensus.

BACKGROUND: There are limited data to guide the diagnosis and management of vasa previa. Currently, what is known is largely based on case reports or series and cohort studies. OBJECTIVE: This study aimed to systematically collect and classify expert opinions and achieve consensus on the diagnosis and clinical management of vasa previa using focus group discussions and a Delphi technique. STUDY DESIGN: A 4-round focus group discussion and a 3-round Delphi survey of an international panel of experts on vasa previa were conducted. Experts were selected on the basis of their publication record on vasa previa. First, we convened a focus group discussion panel of 20 experts and agreed on which issues were unresolved in the diagnosis and management of vasa previa. A 3-round anonymous electronic survey was then sent to the full expert panel. Survey questions were presented on the diagnosis and management of vasa previa, which the experts were asked to rate on a 5-point Likert scale (from "strongly disagree"=1 to "strongly agree"=5). Consensus was defined as a median score of 5. Following responses to each round, any statements that had median scores of ≤3 were deemed to have had no consensus and were excluded. Statements with a median score of 4 were revised and re-presented to the experts in the next round. Consensus and nonconsensus statements were then aggregated. RESULTS: A total of 68 international experts were invited to participate in the study, of which 57 participated. Experts were from 13 countries on 5 continents and have contributed to >80% of published cohort studies on vasa previa, as well as national and international society guidelines. Completion rates were 84%, 93%, and 91% for the first, second, and third rounds, respectively, and 71% completed all 3 rounds. The panel reached a consensus on 26 statements regarding the diagnosis and key points of management of vasa previa, including the following: (1) although there is no agreement on the distance between the fetal vessels and the cervical internal os to define vasa previa, the definition should not be limited to a 2-cm distance; (2) all pregnancies should be screened for vasa previa with routine examination for placental cord insertion and a color Doppler sweep of the region over the cervix at the second-trimester anatomy scan; (3) when a low-lying placenta or placenta previa is found in the second trimester, a transvaginal ultrasound with Doppler should be performed at approximately 32 weeks to rule out vasa previa; (4) outpatient management of asymptomatic patients without risk factors for preterm birth is reasonable; (5) asymptomatic patients with vasa previa should be delivered by scheduled cesarean delivery between 35 and 37 weeks of gestation; and (6) there was no agreement on routine hospitalization, avoidance of intercourse, or use of 3-dimensional ultrasound for diagnosis of vasa previa. CONCLUSION: Through focus group discussion and a Delphi process, an international expert panel reached consensus on the definition, screening, clinical management, and timing of delivery in vasa previa, which could inform the development of new clinical guidelines.

Gestational diabetes in twin pregnancies-a pathology requiring treatment or a benign physiological adaptation?

There is level-1 evidence that screening for and treating gestational diabetes in singleton pregnancies reduce maternal and neonatal morbidity. However, similar data for gestational diabetes in twin pregnancies are currently lacking. Consequently, the current approach for the diagnosis and management of gestational diabetes in twin pregnancies is based on the same diagnostic criteria and glycemic targets used in singleton pregnancies. However, twin pregnancies have unique physiological characteristics, and many of the typical gestational diabetes-related complications are less relevant for twin pregnancies. These differences raise the question of whether the greater increase in insulin resistance observed in twin pregnancies (which is often diagnosed as diet-treated gestational diabetes) should be considered physiological and potentially beneficial in which case alternative criteria should be used for the diagnosis of gestational diabetes in twin pregnancies. In this review, we summarize the most up-to-date evidence on the epidemiology, pathophysiology, and clinical consequences of gestational diabetes in twin pregnancies and review the available data on twin-specific screening and diagnostic criteria for gestational diabetes. Although twin pregnancies are associated with a higher incidence of diet-treated gestational diabetes, diet-treated gestational diabetes in twin pregnancies is less likely to be associated with adverse outcomes and accelerated fetal growth than in singleton pregnancies and may reduce the risk for intrauterine growth restriction. In addition, there is currently no evidence that treatment of diet-treated gestational diabetes in twin pregnancies improves outcomes, whereas preliminary data suggest that strict glycemic control in such cases might increase the risk for intrauterine growth restriction. Overall, these findings provide support to the hypothesis that the greater transient increase in insulin resistance observed in twin pregnancies is merely a physiological exaggeration of the normal increase in insulin resistance observed in singleton pregnancies (that is meant to support 2 fetuses) rather than a pathology that requires treatment. These data illustrate the need to develop twin-specific screening and diagnostic criteria for gestational diabetes to avoid overdiagnosis of gestational diabetes and to reduce the risks associated with overtreatment of diet-treated gestational diabetes in twin pregnancies. Although data on twin-specific screening and diagnostic criteria are presently scarce, preliminary data suggest that the optimal screening and diagnostic criteria in twin pregnancies are higher than those currently used in singleton pregnancies.

Is Increasing Parity Associated with Adverse Perinatal Outcomes in Dichorionic Twin Gestations?

OBJECTIVE: Dichorionic twins have increased risk of preterm birth and hypertensive disorders of pregnancy. Grand multiparity may be associated with adverse perinatal outcomes in singleton pregnancies, although the effect of increasing parity in twins is unclear. This study aimed to elucidate whether grand multiparity leads to adverse outcomes in dichorionic twins compared with multiparity and nulliparity. STUDY DESIGN: This was a retrospective review of dichorionic twins at a single institution between January 2008 and December 2019 comparing pregnancy outcomes among grand multiparity, multiparity, and nulliparity. Primary outcome was preterm birth less than 37 weeks. Multivariable regression controlled for differing demographics, prior preterm birth, use of reproductive technologies, and hypertensive disorders of pregnancy. Chi square and Fisher's exact were used for categorical variables and Kruskal-Wallis was used for continuous variables. RESULTS: A total of 843 (60.3%) pregnancies were nulliparous, 499 (35.7%) multiparous, and 57(4.1%) grand multiparous. Univariate analysis indicated that multiparous women had lower incidence of preterm birth less than 37, 34, and 32 weeks (57 vs. 51%, p = 0.04; 19.2 vs. 14.0%, p = 0.02; 9.6 vs. 5.6%, p = 0.01) and that grand multiparous women had lower incidence of preterm birth less than 34 weeks (19.2 vs. 5.3%, p = 0.008) compared with nulliparous women. Multivariable regression confirmed multiparous women had lower odds of preterm birth less than 34 and 32 weeks compared with nulliparous women (<34 wk: odds ratio [OR] = 0.69, 95% confidence interval [CI] = 0.49-0.97, p = 0.03; <32 wk: OR = 0.48, 95% CI = 0.29-0.79, p = 0.004) and that multiparous women (OR = 0.57, 95% CI = 0.42-0.77, p = 0.0002) and grand multiparous women (OR = 0.23, 95% CI = 0.08-0.68, p = 0.0074) had lower incidence of hypertensive disorders of pregnancy when compared with nulliparous women. CONCLUSION: Grand multiparity is not associated with adverse perinatal outcomes compared with nulliparity or multiparity in dichorionic twins. Increasing parity may protect against incidence of preterm birth and hypertensive disorders of pregnancy even among grand multiparous women. KEY POINTS: · Incidence of preterm birth may decrease with increasing parity in twins.. · Hypertensive disorders of pregnancy may decrease with increasing parity in twins.. · Grand multiparity is not associated with adverse perinatal outcomes in twins..

National and international guidelines on the management of twin pregnancies: a comparative review.

Twin gestations are associated with increased risk of pregnancy complications. However, high-quality evidence regarding the management of twin pregnancies is limited, often resulting in inconsistencies in the recommendations of various national and international professional societies. In addition, some recommendations related to the management of twin gestations are often missing from the clinical guidelines dedicated to twin pregnancies and are instead included in the practice guidelines on specific pregnancy complications (eg, preterm birth) of the same professional society. This can make it challenging for care providers to easily identify and compare recommendations for the management of twin pregnancies. This study aimed to identify, summarize, and compare the recommendations of selected professional societies from high-income countries on the management of twin pregnancies, highlighting areas of both consensus and controversy. We reviewed clinical practice guidelines of selected major professional societies that were either specific to twin pregnancies or were focused on pregnancy complications or aspects of antenatal care that may be relevant for twin pregnancies. We decided a priori to include clinical guidelines from 7 high-income countries (United States, Canada, United Kingdom, France, Germany, and Australia and New Zealand grouped together) and from 2 international societies (International Society of Ultrasound in Obstetrics and Gynecology and the International Federation of Gynecology and Obstetrics). We identified recommendations regarding the following care areas: first-trimester care, antenatal surveillance, preterm birth and other pregnancy complications (preeclampsia, fetal growth restriction, and gestational diabetes mellitus), and timing and mode of delivery. We identified 28 guidelines published by 11 professional societies from the 7 countries and 2 international societies. Thirteen of these guidelines focus on twin pregnancies, whereas the other 16 focus on specific pregnancy complications predominantly in singletons but also include some recommendations for twin pregnancies. Most of the guidelines are recent, with 15 of the 29 guidelines published over the past 3 years. We identified considerable disagreement among guidelines, primarily in 4 key areas: screening and prevention of preterm birth, using aspirin to prevent preeclampsia, defining fetal growth restriction, and the timing of delivery. In addition, there is limited guidance on several important areas, including the implications of the "vanishing twin" phenomenon, technical aspects and risks of invasive procedures, nutrition and weight gain, physical and sexual activity, the optimal growth chart to be used in twin pregnancies, the diagnosis and management of gestational diabetes mellitus, and intrapartum care.This consolidation of key recommendations across several clinical practice guidelines can assist healthcare providers in accessing and comparing recommendations on the management of twin pregnancies and identifies high-priority areas for future research based on either continued disagreement among societies or limited current evidence to guide care.

Outcomes of Elective Compared to Non-Elective Fetal Reduction by Radiofrequency Ablation in Monochorionic Multifetal Pregnancies.

INTRODUCTION: Higher order fetal gestation is associated with adverse pregnancy outcomes, and monochorionic (MC) pregnancies have unique complications. Multifetal pregnancy reduction (MPR) by radiofrequency ablation (RFA) may be used to optimize the outcomes of a single fetus. The purpose of this study was to determine whether pregnancy outcomes differ for elective reduction compared to reduction for medically complicated MC multifetal pregnancies. METHODS: This was a retrospective cohort of patients with MC twins and higher order multiples who underwent MPR via RFA at a single institution between 2008 and 2021. Patients undergoing elective reduction were compared to patients undergoing reduction due to a complication of MC pregnancy. Pregnancy outcomes were evaluated. RESULTS: Forty-eight patients who underwent RFA reduction between 2008 and 2021 were included in the analysis. Sixteen patients (33.3%) underwent elective RFA for MPR, and 32 (66.7%) underwent an RFA procedure for a complicated pregnancy. All pregnancies with RFA performed for elective indication had a continuing pregnancy (live birth rate 100%). There were no reported pregnancy losses within 4 weeks of the procedure when performed for a solely elective indication (n = 0) compared to 6.3% of complicated multifetal pregnancy (n = 2; 6.3%) (p = 0.001). CONCLUSION: In this retrospective cohort study, elective reduction of MC twins using RFA was associated with no cases of fetal loss or PPROM within 4 weeks of the procedure and a 100% live birth rate.

Maternal Morbidity with Repeated Cesarean Deliveries.

OBJECTIVE: This study aimed to estimate the association between adverse maternal outcomes and the number of repeated cesarean deliveries (CDs) in a single obstetrical practice. STUDY DESIGN: Retrospective cohort study of all CDs between 2005 and 2020 in a single maternal fetal medicine practice. We used electronic records to get baseline characteristics and pregnancy/surgical outcomes based on the number of prior CDs. We performed two subgroup analyses for women with and without placenta previa. Chi-square for trend and one-way analysis of variance (ANOVA) were used. RESULTS: A total of 3,582 women underwent CD and met inclusion criteria. Of these women, 1,852 (51.7%) underwent their first cesarean, 950 (26.5%) their second, 382 (10.7%) their third, 191 (5.3%) their fourth, 117 (3.3%) their fifth, and 84 (2.3%) their sixth or higher CDs. The incidence of adverse outcomes (placenta accreta, uterine window, uterine rupture, hysterectomy, blood transfusion, cystotomy, bowel injury, need for a ventilator postpartum, intensive care unit admission, wound complications, thrombosis, reoperation, and maternal death) increased with additional CDs. However, the absolute rates remained low. In women without a placenta previa, the likelihood of adverse outcome did not differ across groups. In women with a placenta previa, adverse outcomes increased with increasing CDs. However, the incidence of placenta previa did not increase with increasing CDs (<5% in each group). The incidence of a uterine dehiscence increased significantly with additional CDs: first, 0.2%; second, 2.0%; third, 6.6%; fourth, 10.3%; fifth, 5.8%; and sixth or higher, 10.4% (p < 0.001). CONCLUSION: Maternal morbidity increases with CDs, but the absolute risks remain low. For women without placenta previa, increasing CDs is not associated with maternal morbidity. For women with placenta previa, risks are highest, but the incidence of placenta previa does not increase with successive CDs. The likelihood of uterine dehiscence increases significantly with increasing CDs which should be considered when deciding about timing of delivery in this population. KEY POINTS: · Maternal morbidity increase with each CD.. · Absolute adverse outcomes remains low in highest order CDs.. · In women without placenta previa, there is no added morbidity with additional CDs..

Clinician-reported chorionicity and zygosity assignment using single-nucleotide polymorphism-based cell-free DNA: Lessons learned from 55,344 twin pregnancies.

OBJECTIVE: Prenatal chorionicity assessment relies on ultrasound, which can be confounded by many factors. Noninvasive assessment of zygosity is possible using single nucleotide polymorphism (SNP)-based cell-free DNA testing. Our objective was to determine the relationship between provider-reported chorionicity and SNP-cfDNA assignment of twin zygosity. METHODS: All twin pregnancy blood samples received by a reference laboratory between September 27, 2017 and September 8, 2021 were included. Chorionicity assignment was requested on the requisition, recorded as; monochorionic (MC), dichorionic, or "don't know". SNP-cfDNA zygosity results, monozygotic (MZ) or dizygotic (DZ), were correlated with chorionicity assignment. RESULTS: 59,471 twin samples (median gestational age = 12.0 weeks at draw) were received and analyzed; 55,344 (93.1%) received zygosity assignment. SNP-cfDNA reported 16,673 (30.1%) MZ and 38,671 (69.9%) as DZ. Provider-reported chorionicity was compared to the zygosity assignment for each case. Of 6283 provider-reported MC twins, 318 (5.1%) were reported as DZ using SNP-cfDNA. CONCLUSION(S): One in 20 suspected MC twin pregnancies were reported as DZ using SNP-cfDNA. Approximately 30% of 55,344 twin pregnancies were found to be MZ, including cases where chorionicity was unknown. SNP-cfDNA zygosity assessment is a useful adjunct assessment for twin pregnancies, particularly those reported as MC or without determined chorionicity.

Should twin-specific growth charts be used to assess fetal growth in twin pregnancies?

One of the hallmarks of twin pregnancies is the slower rate of fetal growth when compared with singleton pregnancies during the third trimester. The mechanisms underlying this phenomenon and whether it represents pathology or benign physiological adaptation are currently unclear. One important implication of these questions relates to the type growth charts that should be used by care providers to monitor growth of twin fetuses. If the slower growth represents pathology (ie, intrauterine growth restriction caused uteroplacental insufficiency), it would be preferable to use a singleton growth chart to identify a small twin fetus that is at risk for perinatal mortality and morbidity. If, however, the relative smallness of twins is the result of benign adaptive mechanisms, it is likely preferable to use a twin-based charts to avoid overdiagnosis of intrauterine growth restriction in twin pregnancies. In the current review, we addressed this question by describing the differences in fetal growth between twin and singleton pregnancies, reviewing the current knowledge regarding the mechanisms responsible for slower fetal growth in twins, summarizing available empirical evidence on the diagnostic accuracy of the 2 types of charts for intrauterine growth restriction in twin pregnancies, and addressing the question of whether uncomplicated dichorionic twins are at an increased risk for fetal death when compared with singleton fetuses. We identified a growing body of evidence that shows that the use of twin charts can reduce the proportion of twin fetuses identified with suspected intrauterine growth restriction by up to 8-fold and can lead to a diagnosis of intrauterine growth restriction that is more strongly associated with adverse perinatal outcomes and hypertensive disorders than a diagnosis of intrauterine growth restriction based on a singleton-based chart without compromising the detection of twin fetuses at risk for adverse outcomes caused by uteroplacental insufficiency. We further found that small for gestational age twins are less likely to experience adverse perinatal outcomes or to have evidence of uteroplacental insufficiency than small for gestational age singletons and that recent data question the longstanding view that uncomplicated dichorionic twins are at an increased risk for fetal death caused by placental insufficiency. Overall, it seems that, based on existing evidence, the of use twin charts is reasonable and may be preferred over the use of singleton charts when monitoring the growth of twin fetuses. Still, it is important to note that the available data have considerable limitations and are primarily derived from observational studies. Therefore, adequately-powered trials are likely needed to confirm the benefit of twin charts before their use is adopted by professional societies.

The association between sonographic cervical length components and preterm birth in women with ultrasound- or exam-indicated cerclage.

OBJECTIVE: To evaluate which parameters of a sonographic cervical length measurement are associated with preterm birth in women with ultrasound- or exam-indicated cerclage. METHODS: This was a retrospective cohort study of women with singleton pregnancies who underwent ultrasound- or exam-indicated Shirodkar cerclage by a single maternal-fetal medicine practice between 2011 and 2019. All patients underwent sonographic cervical length measurement 2-3 weeks after cerclage placement, and then every 2-4 weeks up to 32 weeks. The images from the first and second post-cerclage cervical lengths were reviewed. Total cervical length, upper cervical length (from the internal cervical os to the cerclage), and lower cervical length (from the cerclage to the external os) were measured. The primary outcome for this study was gestational age at delivery. RESULTS: A total of 114 women with cerclage were included (85 (74.6%) ultrasound-indicated and 29 (25.4%) exam-indicated). The first and second total cervical lengths correlated with gestational age at delivery (r = 0.26, p=.005; r = 0.33, p<.001, respectively), and the change from first to second was inversely correlated with gestational age at delivery (r = -0.20, p=.032). The first and second upper cervical lengths also correlated with gestational age at delivery (r = 0.22, p = .019; r = 0.33, p<.001, respectively), and the change from first to second upper cervical length was inversely correlated with gestational age at delivery (r= -0.20, r = 0.029). Neither the first nor the second lower cervical lengths were significantly associated with gestational age at delivery. On regression analysis, total cervical length and upper cervical length were not independently associated with gestational age at delivery (p = .108 and p=.806, respectively, for the first scan; p = .153 and p=.166, respectively, for the second scan). CONCLUSIONS: Postcerclage total cervical length and upper cervical length are both associated with gestational age at delivery and risk of preterm birth, but not independently. After ultrasound- or exam-indicated cerclage, sonographic monitoring of either the total cervical length or the upper cervical length might be predictive of gestational age at delivery and the risk of preterm birth.

ACGME Milestones in global health: Need for standardized assessment of global health training in obstetrics/gynecology residency.

Collective interest in global health training during US obstetrics/gynecology (Ob/Gyn) residency has grown over the past decade. The benefits of participation in global health electives have been well described. This review seeks to determine what literature exists regarding the use of Accreditation Council for Graduate Medical Education (ACGME) Milestones in Ob/Gyn residency as an assessment tool to evaluate global health programs. The PubMed database was searched from July 14, 2020 to August 20, 2021, using six search phrases: "global health curriculum(s) and ACGME"; "international health and ACGME"; "global health and Ob/Gyn residency"; "international health and Ob/Gyn residency"; "global health and Ob/Gyn residents"; and "global health curriculum(s) and Ob/Gyn residency." Publications that described global health programming outside of residency, within other medical specialties, and/or at non-US institutions were excluded from this review. In total, 259 publications resulted from the preliminary search. Five articles described US global health residency training in Ob/Gyn in some capacity. Only one publication described a specific global health elective and its evaluation with respect to ACGME Milestones. Despite growing popularity of global health electives among residency programs, few are assessing the educational value of these offerings using ACGME Milestones or describing these efforts in the literature.

Arcuate Uterus as an Independent Risk Factor for Adverse Pregnancy Outcomes.

OBJECTIVE: The aim of the study is to estimate the association between arcuate uterus and pregnancy outcomes using controls selected from a similarly high-risk cohort. STUDY DESIGN: This is a retrospective cohort study of women with an arcuate uterus cared for by a single maternal-fetal medicine practice from 2005 to 2020. We included all women with a singleton pregnancy ≥20 weeks and diagnosis of arcuate uterus and randomly selected (3:1) patients with a singleton pregnancy and no uterine anomaly from the same practice as controls. Baseline characteristics and pregnancy outcomes were compared between the two groups. Chi-square, Fisher's exact, and independent samples t-test were used for data analysis, as indicated. RESULTS: A total of 37 women with an arcuate uterus (55 independent singleton pregnancies) and 165 controls were included. There were no differences in baseline characteristics. Women with an arcuate uterus had a significantly higher rate of spontaneous preterm birth less than 37 weeks (10.9 vs. 3.0%, p = 0.031) and were more likely to require vaginal progesterone (5.5 vs. 0.6%, p = 0.049) and administration of antenatal corticosteroids (16.4 vs. 5.5%, p = 0.020). Arcuate uterus was also associated with lower birthweight (3,028.1 ± 528.0 vs. 3257.2 ± 579.9 g, p = 0.010) and higher incidence of intrauterine fetal growth restriction (20.0 vs. 7.3%, p = 0.008), despite similar starting body mass index (BMI) and weight gain throughout pregnancy. There were no differences in preeclampsia, malpresentation, cesarean delivery, blood transfusion, retained placenta, or morbidly adherent placenta. CONCLUSION: Arcuate uterus is associated with a significantly increased risk of spontaneous preterm birth (<37 weeks), need for vaginal progesterone for short cervix and antenatal corticosteroids, fetal growth restriction, and lower mean birthweight. These findings suggest that arcuate uterus is not just a normal variant of uterine anatomy but rather a risk factor for poor fetal growth, short cervix, and a higher risk pregnancy. KEY POINTS: · Arcuate uterus is associated with increased risk of preterm birth and fetal growth restriction.. · Women with arcuate uteri had higher rates of vaginal progesterone use during pregnancy.. · Arcuate uterus should be treated as a true finding rather than a normal anatomical variant..

Mode of Delivery in Monochorionic Compared With Dichorionic Twin Pregnancies.

OBJECTIVE: To compare mode of delivery between monochorionic and dichorionic twin pregnancies. METHODS: This was a retrospective cohort study of women undergoing delivery of diamniotic twins in a single maternal-fetal medicine practice in New York City between 2005 and 2021. We compared baseline characteristics and delivery outcomes between monochorionic and dichorionic gestations. The primary outcome was mode of delivery. For monochorionic-diamniotic twin pregnancies at or after 34 weeks of gestation, we also compared neonatal outcomes between women who did and did not attempt vaginal delivery. Data were analyzed using the χ2 test, Fisher exact test, and t test when appropriate. RESULTS: A total of 1,121 diamniotic twin pregnancies were identified, of which 202 (18%) were monochorionic and 919 (82%) were dichorionic. Mode of delivery did not differ between monochorionic and dichorionic pregnancies, both in the overall cohort (cesarean delivery rate 61% vs 63%, P=.54) and in the subgroup of women who attempted vaginal delivery (cesarean delivery rate 22% vs 21%, P=.80). For patients with a vaginal delivery of twin A, the mode of delivery for twin B did not differ between the groups. Among the patients with monochorionic pregnancies at or after 34 weeks of gestation, neonatal outcomes did not differ between women who did and did not attempt vaginal delivery. CONCLUSION: Monochorionic-diamniotic pregnancies are not at an increased risk of cesarean delivery when compared with their dichorionic-diamniotic counterparts.

Elective fetal reduction by radiofrequency ablation in monochorionic diamniotic twins decreases adverse outcomes compared to ongoing monochorionic diamniotic twins.

BACKGROUND: Multifetal pregnancy reduction is a technique used to reduce the fetal number to mitigate the risks of adverse outcomes associated with multiple gestations. Monochorionic diamniotic twin pregnancies are subject to unique complications, contributing to adverse pregnancy outcomes. Thus, patients have an option to electively reduce 1 fetus to improve outcomes. OBJECTIVE: This study aimed to compare outcomes of elective reduction of monochorionic diamniotic twins by radiofrequency ablation to planned ongoing monochorionic diamniotic twins. STUDY DESIGN: We performed a retrospective review of 315 monochorionic diamniotic twin gestations that underwent first-trimester ultrasound within 1 institution. Planned electively reduced twins were compared with ongoing monochorionic diamniotic twins. All reductions were performed via radiofrequency ablation of the cord insertion site into the fetal abdomen. The primary outcome was preterm birth at <36 weeks' gestation. Secondary outcomes included gestational age at delivery; preterm birth at less than 37-, 34-, 32-, and 28-weeks' gestation; unintended loss; and adverse perinatal outcomes. RESULTS: Among 315 monochorionic diamniotic pregnancies, 14 (4.4%) underwent elective multifetal pregnancy reduction, and 301 (95.6%) were planned ongoing twins. The mean gestational age of radiofrequency ablation in the elective multifetal pregnancy reduction group was 15.1±0.68 weeks. Patients who underwent elective multifetal pregnancy reduction had significantly higher maternal age (P<.01) and were more likely to be Asian (P<.01). Moreover, they were more likely to have undergone in vitro fertilization (P=.03) and chorionic villus sampling (P<.01). There was a significantly higher rate of term deliveries in the elective radiofrequency ablation group compared with ongoing twins (gestational age, 38 weeks [interquartile range, 36.1-39.1] vs 35.9 weeks [interquartile range, 34.0-36.9]; P<.01). Patients with ongoing pregnancies had a trend of increased rate of preterm birth at <36 weeks' gestation (odds ratio, 3.4; 95% confidence interval, 1.0-12.0; P=.06), a significantly increased risk of preterm birth at <37 weeks' gestation (odds ratio, 8.0; 95% confidence interval, 2.4-26.4; P<.01), and no difference at less than 34-, 32-, or 28- weeks' gestation. All patients who underwent elective radiofrequency ablation had successful pregnancies with no pregnancy losses or terminations. Of ongoing gestations, 36 required procedures, including 16 (5.3%) medically indicated radiofrequency ablation, 14 (4.6%) laser ablation, and 6 (1.9%) amnioreductions. Furthermore, 22 patients (7.3%) with planned ongoing twins had total pregnancy loss at <24 weeks' gestation. Notably, 12 patients (4.0%) had unintended loss of 1 fetus before 24 weeks' gestation in the ongoing pregnancy cohort, and 12 patients (4.0%) had unintended loss of both fetuses before 24 weeks' gestation. Moreover, 5 patients (1.7%) in the ongoing pregnancy group had intrauterine fetal demise at >24 weeks' gestation and 10 patients (3.3%) electively terminated both fetuses. There was no significant difference in loss rates between the 2 groups. CONCLUSION: In this study of monochorionic diamniotic twins, patients who elected to undergo multifetal pregnancy reduction had significantly lower rates of preterm birth at <37 weeks and a lower trend of preterm birth at <36 weeks' gestation without an increased risk of pregnancy loss. Median gestational age at delivery was significantly higher in the elective multifetal pregnancy reduction group (38 weeks) than in the ongoing pregnancy group (35.9 weeks). Further research is needed to clarify if multifetal pregnancy reduction improves long-term outcomes.

Non-invasive prenatal testing in the management of twin pregnancies.

Twin pregnancies are common and associated with pregnancy complications and adverse outcomes. Prenatal clinical management is intensive and has been hampered by inferior screening and less acceptable invasive testing. For aneuploidy screening, meta-analyses show that non-invasive prenatal testing (NIPT) through analysis of cell-free DNA (cf-DNA) is superior to serum and ultrasound-based tests. The positive predictive value for NIPT is driven strongly by the discriminatory power of the assay and only secondarily by the prior risk. Uncertainties in a priori risks for aneuploidies in twin pregnancies are therefore of lesser importance with NIPT. Additional information on zygosity can be obtained using NIPT. Establishing zygosity can be helpful when chorionicity was not reliably established early in pregnancy or where the there is a concern for one versus two affected fetuses. In dizygotic twin pregnancies, individual fetal fractions can be measured to ensure that both values are satisfactory. Vanishing twins can be identified by NIPT. Although clinical utility of routinely detecting vanishing twins has not yet been demonstrated, there are individual cases where cf-DNA analysis could be helpful in explaining unusual clinical or laboratory observations. We conclude that cf-DNA analysis and ultrasound have synergistic roles in the management of multiple gestational pregnancies.

The Association between Placental Histopathology, Fetal Growth Restriction, and Preeclampsia in Twin Pregnancies.

OBJECTIVE: This study aims to estimate the association between abnormal placental histopathology, fetal growth restriction (FGR), and preeclampsia (PEC) in twin pregnancies. STUDY DESIGN: Retrospective cohort study of women with diamniotic twin pregnancies with live births at ≥24 weeks of gestation and available placental pathology. Findings were compared between women with and without FGR, which was defined as a birthweight <10th percentile, using singleton and twin growth curves, and those with and without PEC. The primary study outcome was a composite of abnormal placental histopathology. Chi-square, Fisher's exact, and Student's t-tests were used for analysis. RESULTS: Among 859 patients with diamniotic twins, 806 (93.8%) had placental pathology. A total of 422 (52.4%) women had at least one twin with FGR, using a singleton growth curve. FGR affected 136 (16.9%) pregnancies when a twin growth curve was applied. There was no significant difference in composite outcome between groups, using either growth curve (45.5 vs. 44.8%, p = 0.84; adjusted odds ratio (aOR): 1.06, 95% CI: 0.79-1.40 and 52.2 vs. 43.7%, p = 0.07; aOR: 1.44, 95% CI: 0.90-2.10). A total of 122 of 789 (15.5%) patients developed PEC. There was no significant difference in composite outcome between patients with and without PEC (41.8 vs. 45.4%, p = 0.46; aOR: 0.79, 95% CI: 0.53-1.18). CONCLUSION: In twin pregnancies, FGR and PEC are not associated with abnormal placental histopathology. This suggests that the pathologic placental manifestations of these conditions may differ in twins and include factors other than those commonly described in singletons.

Two decades of interventions in New York State to reduce maternal mortality: a systematic review.

OBJECTIVE: To perform a systematic review of interventions to reduce maternal mortality in New York. STUDY DESIGN: We conducted a systematic review of literature published between 2000 and January 2019 reporting interventions to reduce maternal mortality in New York using PubMed and search terms: pregnancy-related death or maternal mortality OR maternal death AND New York. Eight hundred and ninety-three articles were reviewed by title, content, and focus on New York interventions or policies. Ten met inclusion criteria. A second review of the Safe Motherhood Initiative (SMI) identified an additional six articles. RESULTS: Nine articles described hospital-based initiatives; one described a community-based initiative. No prospective randomized controlled trials in a nonsimulated setting were identified. Several articles described SMI bundles; one tested simulated checklist implementation. Three presented results of bundle implementation but did not significantly impact measured maternal mortality and/or morbidity. The single community-based initiative provided doulas to low-income women, yielding significantly lower rates of preterm birth and low birthweight, but no difference in cesarean deliveries compared to other women in the community. CONCLUSION: Current hospital-based interventions have not reduced maternal mortality in New York. The single community-based intervention identified reduced adverse birth outcomes. Continued concern about maternal mortality in New York suggests community-based approaches should be considered to affect change in conjunction with longer term hospital-based interventions.

The association between high-normal blood pressure and the development of preeclampsia in twin pregnancies.

Objective: We sought to determine if women with twin pregnancies and blood pressure (BP) above the 95th percentile but within normal ranges (i.e. less than 140 systolic and 90 diastolic) are at increased risk of hypertensive disorders of pregnancy.Methods: Retrospective cohort study of all women with twin pregnancies being cared for by a single Maternal Fetal Medicine practice between 2012 and 2018. We identified all women who had a systolic blood pressure (SBP) or diastolic blood pressure (DBP) above the 95th percentile but less than 140 systolic and 90 diastolic at any point during pregnancy. Based on prior publications, the 95th percentile was defined as: a SBP 121-139 mmHg up to 30 weeks or 131-139 mmHg after 30 weeks, a DBP 81-89 mmHg up to 34 weeks or 85-89 mmHg after 34 weeks. We excluded women diagnosed with chronic hypertension either before or during pregnancy. The primary outcome was the development of preeclampsia. Chi-square and logistic regression were used.Results: A total of 457 patients met the inclusion criteria, of whom 109 (23.9%) had either a systolic or diastolic BP above the 95th percentile (but normal) at any time during pregnancy. These women were significantly more likely to develop preeclampsia (30.3 versus 12.6%, p < .001, aOR 2.32 (1.31, 4.09)) and gestational hypertension without preeclampsia (16.5 versus 4.6%, p < .001, aOR 4.27 (2.01, 9.07)).Conclusions: In women with twin pregnancies, a high-normal systolic or diastolic BP (above 120 systolic or 80 diastolic prior to 30 weeks, or above 130 systolic or 84 diastolic after 30 weeks) is associated with a significantly increased risk of gestational hypertension and preeclampsia.

Change in cervical length and spontaneous preterm birth in nulliparous women with a history of loop electrosurgical excision procedure.

BACKGROUND: Prior studies have shown an association between history of loop electrode procedures (LEEP) and spontaneous preterm delivery (SPTD) independent of mid-trimester cervical length. These studies suggest that there may be other factors beyond an individual cervical length, which contribute to identifying at-risk pregnancies. OBJECTIVE: The objective of this study is to determine the association between change in cervical length and SPTD in women with a history of LEEP. STUDY DESIGN: This is a retrospective cohort study of singleton nulliparous women with a history of LEEP who received serial cervical length measurements at a single institution between 2012 and 2016. Women with serial cervical lengths and available outcome data were included. The cervical length at different gestational ages and the rate of change in length were compared with the risk for SPTD <37 weeks using Student's t-test. RESULTS: One-hundred-thirty subjects met the inclusion criteria for the study. The mean cervical length (35.3 versus 39.8 mm, p = .042 at 16 weeks; 32.2 versus 37.8 mm, p < .01 at 20 weeks; 29.9 versus 35.6 mm, p = .027 at 24 weeks; 21.6 versus 33.4 mm, p < .01 at 28 weeks) was significantly different between women who had an SPTD <37 weeks compared to women who did not. The average rate of change in transvaginal cervical length between 16 to 28 weeks was significantly different between women who had an SPTD <37 weeks compared to women who did not (-1.4 versus 0.4 mm/week, p < .01). CONCLUSION: Women with a history of LEEP who had an SPTD <37 weeks had a shorter cervical length at 16, 20, 24, and 28 weeks' gestation and a higher rate of change in cervical length between 16 and 28 weeks than women without a history of SPTD. Our findings support the concept of the preterm birth syndrome as an evolving biophysical process rather than a distinct event, suggesting improved prediction in the setting of prior history of a LEEP with serial imaging.

A Case Report to Assess Passive Immunity in a COVID Positive Pregnant Patient.

INTRODUCTION: Data regarding transplacental passage of maternal coronavirus disease 2019 (COVID-19) antibodies and potential immunity in the newborn is limited. CASE REPORT: We present a 25-year-old multigravida with known red blood cell isoimmunization, who was found to be COVID-19 positive at 27 weeks of gestation while undergoing serial periumbilical blood sampling and intrauterine transfusions. Maternal COVID-19 antibody was detected 2 weeks after positive molecular testing. Antibodies were never detected on cord blood samples from two intrauterine fetal cord blood samples as well as neonatal cord blood at the time of delivery. CONCLUSION: This case demonstrates a lack of passive immunity of COVID-19 antibodies from a positive pregnant woman to her fetus, neither in utero nor at the time of birth. Further studies are needed to understand if passage of antibodies can occur and if that can confer passive immunity in the newborn. KEY POINTS: · Passive immunity should not be assumed in COVID-19 infection in pregnancy.. · Isoimmunization may impair passive immunity of certain antibodies.. · Vaccination to or maternal infection of COVID-19 may not be protective for the fetus..