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Importance Monochorionic (MC) twins are hemodynamically connected by vascular anastomoses within the single shared placenta. The transfer of fluid or blood from one fetus to the other may result in development of pathologic complications, such as twin-twin transfusion syndrome, twin anemia polycythemia sequence, selective intrauterine growth restriction, and twin reversed arterial perfusion sequence. Monoamniotic gestations, which comprise a small fraction of MC pregnancies, can also present with unique challenges, particularly antepartum umbilical cord entanglement. All these complications carry a high risk of fetal morbidity and mortality if not recognized and managed in a timely fashion. Objective The purpose of this article is to review evidence-based management of complicated MC twin gestations and propose a standardized approach to surveillance. Evidence Acquisition Monochorionic gestations account for the majority of complications that occur in twin pregnancies; however, there is unclear evidence on the appropriate surveillance for and management of specific complications associated with these pregnancies. Results This article summarizes management for each specific type of MC complication in a structured and clear manner. Conclusions Early pregnancy ultrasound, ideally between 10 and 13 weeks' gestation, is critical for the diagnosis and characterization of twin pregnancies. To improve outcomes for MC twins, appropriate fetal surveillance should be initiated at 16 weeks' gestation and continued until delivery. Relevance Improve perinatal outcomes in MC twin pregnancies. Target Audience Obstetricians and gynecologists, family physicians Learning Objectives After completing this activity, the learner should be better able to describe the sonographic findings used to establish the diagnosis of MC twin pregnancies; identify complications unique to MC twins pregnancies, including twin-twin transfusion syndrome, twin reversed arterial perfusion sequence, twin anemia polycythemia syndrome, co-twin demise, cord entanglement, and conjoined twins; and explain the management of complications associated with MC twin pregnancies.

AbstractObjectivesThe purpose of this study was to evaluate the reproducibility of stomach position grading in congenital diaphragmatic hernia (CDH) as proposed by Cordier et al and Basta et al after standardization of the methods at our center.MethodsWe collected sonographic images from 23 fetuses with left‐sided CDH at our center from 2010 to 2018. Nine operators (one maternal fetal medicine expert and eight sonographers) reviewed the selected images and graded the stomach position according to the methods of Cordier et al and Basta et al. We assessed the interoperator agreement with Fleiss's kappa statistics.ResultsOverall agreement amongst all operators was moderate for both methods proposed by Cordier et al (k = 0.60, SE 0.07, 95% CI 0.47‐0.73, P < .0001) and Basta et al (k = 0.60, SE 0.06, 95% CI 0.47‐0.73, P < .0001). Interoperator agreement was moderate for grade 3 with the method by Cordier et al (k = 0.45, SE 0.09, 95% CI 0.27‐0.64, P < .0001) and fair for grade 4 with the method by Basta et al (k = 0.33, SE 0.08, 95% CI 0.18‐0.49 P < .0001).ConclusionsOur study demonstrates a fair to moderate interoperator agreement of the stomach position grading methods proposed in the literature after standardization of the methods at our center. Further multicenter studies are needed to confirm our results.

ObjectivesThe aim of this study was to investigate the reproducibility of a standardized method to assess the ultrasound liver‐to‐thoracic area ratio in fetuses with congenital diaphragmatic hernia.MethodsWe selected 24 images of 9 fetuses diagnosed with left‐sided at our institution between January 2010 and December 2017. Eight operators (1 maternal‐fetal medicine specialist and 7 sonographers) reviewed the selected images and assessed the ultrasound liver‐to‐thoracic area ratio according to a standardized protocol. We evaluated the correlation between operators using the intraclass correlation coefficient and compared agreement between the sonographers and a physician with experience in measuring the ultrasound liver‐to‐thoracic area ratio using a Bland‐Altman analysis.ResultsGood intraoperator reproducibility was observed for the standardized ultrasound liver‐to‐thoracic area ratio (intraclass correlation coefficient, 0.78). Good agreement among sonographers and the physician was also observed for the standardized measurements (bias, 0.01; precision, 0.03; limits of agreement, –0.05 to + 0.07).ConclusionsWe demonstrated that good intraoperator and interoperator reproducibility of ultrasound liver‐to‐thoracic area ratio assessment is feasible after standardizing the method in our center.

INTRODUCTION: Umbilical vein varix (UVV) is a focal dilation of the fetal umbilical vein. Clinical significance is not clearly established but it has been associated with adverse outcomes. This study investigates the clinical outcomes of UVV diagnosed during pregnancy. METHODS: We performed a multicenter retrospective (USA, Chile, Italy and Brazil) study by reviewing 19 fetuses diagnosed with UVV between 2012 and 2017. We investigated gestational age at diagnosis and at delivery, UVV maximum diameter, fetal gender, associated anatomical anomalies, intrauterine growth restriction, fetal demise, type of delivery, birth weight, Apgar scores. RESULTS: UVV was diagnosed at 26.4+/- 4.4 weeks of gestation. Maximum diameter of the defect at diagnosis typically was 13.1+/- 5mm. The majority of fetuses were male (n=12, 63%). Growth restriction was diagnosed in 26% (n=5) of the fetuses. Seventeen (89%) infants survived. Fetal demise occurred in 2 (11%) patients; one was associated with structural anomalies, and the other fetus did not have any other associated anomaly. Vaginal delivery was performed in 10 (53%) patients; median weight at birth was 2870 g (270-4960 g). Median Apgar scores were 8 and 9 on 1st and 5th minutes consecutively (ranging from 0 to 10). Genetic and anatomical anomalies were present in 21% (n=4) of the fetuses and included: karyotype 47,XY+13, cleft lip and palate, cerebellar hypoplasia, aortic hypoplasia, cardiomegaly, Blake's pouch cyst, ambiguous genitalia, campomelic dysplasia with SOX9 mutation. CONCLUSION: UVV is a rare congenital condition that is usually associated with low frequency of other structural/genetic anomalies and with good prognosis. ACKNOWLEDGEMENTS: Waldo Sepulveda, Edward Araujo Junior, Mari Charisse Trinidad, and Heron Werner

ObjectivesThis study investigated the reproducibility of standardization of lung‐to‐head ratio measurements in congenital diaphragmatic hernia (CDH) at our center among sonographers after we standardized the method.MethodsWe reviewed ultrasound images of 12 fetuses with CDH at Mayo Clinic from 2010 to 2016. Nine operators (1 maternal‐fetal medicine specialist with experience in measuring the lung‐to‐head ratio and 8 sonographers), who were blinded to previous findings, reviewed 33 selected images from 12 fetuses with left CDH. The method for lung‐to‐head ratio measurement was standardized before starting the measurements. The lung‐to‐head ratio was assessed by different methods to obtain the lung areas: anteroposterior, longest, and area tracing. We evaluated the correlation between operators using the intraclass correlation coefficient (ICC). We also compared agreement between the sonographers and a physician with experience in measuring the lung‐to‐head ratio using a Bland‐Altman analysis.ResultsThe methods with the best interoperator reproducibility were the standardized anteroposterior lung‐to‐head ratio (ICC, 0.69) and the standardized lung‐to‐head ratio tracing (ICC, 0.65) compared to the longest lung‐to‐head ratio (ICC, 0.56). The standardized lung‐to‐head ratio tracing had the best agreement among sonographers and the physician (bias, 0.11; limits of agreement, −0.27 to +0.49) than the anteroposterior lung‐to‐head ratio (bias, 0.35; limits of agreement, −0.13 to + 0.83) and the longest lung‐to‐head ratio (bias, 0.27; limits of agreement, −0.35 to +0.89).ConclusionsWe demonstrated that the lung‐to‐head ratio tracing method has high interoperator reproducibility and the best agreement among the operators at our center. Further multicenter studies are necessary to confirm our results.