First trimester ultrasonographic parameters in prediction of the course and outcome of monochorionic twin pregnancies

Abstract

Background/aim: The aim of the study was to evaluate the association and the potential predictive value of first trimester ultrasonographic parameters on the course and outcome of monochorionic diamniotic twin pregnancies. Materials and methods: A prospective cohort study was undertaken of 39 healthy women with consecutive monochorionic diamniotic twin pregnancies. During first-trimester screening, crown-rump length (CRL) and nuchal translucency (NT) were measured. The intertwin discordance in CRL and NT was determined. As pregnancy outcomes we assessed twins' live-born rates, Apgar scores, birth weight, pregnancy complications, and gestational week of delivery. Results: None of the assessed pregnancy outcomes significantly correlated with standard CRL discordance ≥10%. The newly established cut-off was 3.75 mm for CRL and 1.3 mm for NT. Monochorionic diamniotic twins were delivered in a later gestational week and had better chance of survival if CRL intertwin difference was <3.75 mm. Apgar scores significantly negatively correlated only with NT of corresponding twins. When intertwin NT difference was ≥1.3 mm, twins had lower birth weight and pregnancy complications were more frequent. Regression models show that intertwin CRL difference <3.75 mm is a significant predictor of live-born monochorionic diamniotic twins. Conclusion: CRL and NT in monochorionic diamniotic twin pregnancies could indicate pregnancy complications and outcomes.