Monochorionic versus dichorionic twins: Are obstetric outcomes always different?

Area of Science:

• Obstetrics and Gynecology
• Perinatology
• Neonatology

Background:

• Monochorionic diamniotic (MCDA) and dichorionic (DC) twin pregnancies have distinct placental sharing and potential complications.
• Understanding comparative outcomes is crucial for optimizing maternal and neonatal care.

Purpose of the Study:

• To compare obstetric, perinatal, and postpartum outcomes between MCDA and DC twin pregnancies.
• To investigate the impact of twin-to-twin transfusion syndrome (TTTS) on these outcomes.

Main Methods:

• Prospective cohort study design.
• Comparison of outcomes in 228 MCDA and 598 DC twin pregnancies.
• Statistical analysis using Chi square, Fischer's exact, Student's t, and Mann-Whitney tests.

Main Results:

• MCDA pregnancies exhibited higher rates of obstetrical complications (85.5% vs. 75.1%) including preterm premature rupture of membranes and intrauterine growth restriction.
• TTTS occurred in 7.9% of MCDA pregnancies. MCDA pregnancies had earlier delivery and lower birthweights.
• Neonatal intensive care unit (NICU) admission rates were higher for MCDA newborns (50% vs. 38.9%). Postpartum complications were similar.
• Excluding TTTS cases, differences in NICU admissions persisted. Uncomplicated pregnancies showed no significant perinatal outcome differences.

Conclusions:

• MCDA pregnancies are associated with increased obstetrical complications, irrespective of TTTS.
• Despite higher complication rates, uncomplicated MCDA pregnancies demonstrate comparable perinatal outcomes to uncomplicated DC pregnancies.
• These findings highlight the importance of careful monitoring for MCDA pregnancies while reassuring for uncomplicated cases.