Monochorionic versus dichorionic twins: Are obstetric outcomes always different?

This prospective cohort study compared obstetric, perinatal and postpartum outcomes of monochorionic diamniotic (n = 228) versus (vs.) dichorionic (n = 598) twin pregnancies. Statistical analysis was performed using software SPSS® v19.0.0.2. Chi square, Fischer's exact, Student's t and Mann-Withney tests were applied. Obstetrical complications rates were 85.5% vs. 75.1% (p < 0.01). Differences were found in preterm premature rupture of membranes (26.3% vs. 19.3%, p < 0.05) and intrauterine growth restriction (19.7% vs. 10.5%, p < 0.01). Twin-to-twin transfusion syndrome (TTTS) occurred in 7.9% of monochorionic pregnancies. Vaginal delivery occurred in 47.4% vs. 43.1%. Monochorionic pregnancies had earlier gestational ages at delivery and subsequently lower birthweights (p < 0.01). There was no difference in Apgar scores. Admission rate of at least one of the newborns in intensive care unit (NICU) was 50% vs. 38.9% (p < 0.05). Postpartum complications were similar. These results were the same excluding TTTS cases, except for admission in NICU (46.8% vs. 34.9%, p > 0.05). Analysing only the uncomplicated pregnancies (33 vs. 149), there were no differences in perinatal outcomes. We conclude that monochorionic pregnancies had higher rates of obstetrical complications, which were independent of TTTS occurrence in our sample. However, considering only the uncomplicated pregnancies till delivery, there were no significant differences in perinatal outcomes.