Comparative Study of Perinatal Outcome in Uncomplicated Monochorionic Diamniotic versus Dichorionic Diamniotic Twins at a Specialized Twin Clinic—A Prospective Study

Abstract Background  Monochorionic twins have higher perinatal morbidity and mortality than dichorionic twins. However, there is conflicting data on outcomes of uncomplicated monochorionic twins. Purpose of the Study  The aim of this study is to compare the outcomes of apparently uncomplicated monochorionic twins to dichorionic twins. Methods  This is a prospective study conducted from August 2019 to December 2020 at a specialized twin clinic. All twins, whose chorionicity was determined before 14 weeks with two live fetuses at 24 weeks, were recruited. Complicated monochorionic diamniotic (MCDA) twins with twin-to-twin transfusion syndrome, twin anemia polycythemia syndrome, selective fetal growth restriction before 24 weeks and single or double fetal demise before 24 weeks were excluded. Other exclusion criteria were major congenital and chromosomal abnormalities, higher order multiples, monoamniotic twins, and twins with undetermined chorionicity antenatally. Both the groups were followed till delivery and neonates followed till 28 days. Maternal and neonatal outcomes were studied and compared. Results  One-hundred forty-eight mothers with dichorionic diamniotic (DCDA) and 74 with uncomplicated MCDA were studied. Mean gestational age at delivery was 35 weeks in both the groups. Maternal, fetal, and neonatal morbidities were similar in both, except early onset preeclampsia that was higher in the DCDA group. Prospective risk of stillbirth for DCDA and MCDA after 24 weeks was 1.35 and 4.05%, respectively. Prospective risk of stillbirth for DCDA and MCDA after 30 weeks was 1.49 and 0%, respectively. Conclusion  The maternal and perinatal outcomes in uncomplicated MCDA twins are similar to DCDA twins. Prospective risk of stillbirth after 30 weeks is extremely low. Hence, uncomplicated MCDA twins should not be delivered electively before 36 weeks.