Clinical outcomes of first trimester discordant twins

Objective: To compare the clinical outcomes of first trimester discordant twins with second or third trimester discordant twins and concordant twins. Methods: Pregnancy outcomes of twin pregnancies delivered from October 1994 to February 2006 were analyzed retrospectively. Subjects were categorized into following three groups: 1) group 1, first trimester discordant twins defined as intertwin CRL difference 5 days at 10-14 weeks of gestation (n=32), 2) group 2, second or third trimester discordant twins defined as intertwin AC difference >20 mm at 20-28 weeks of gestation or intertwin fetal weight difference >25% beyond 29 weeks of gestation (n=42), 3) group 3, concordant twins with no discordancy throughout the whole gestation (n=723). Perinatal complications analyzed for were congenital anomaly, fetal growth restriction (FGR), fetal death in utero (FDIU). Results: The three groups were similar with respect to maternal characteristics and chorionicity. Overall, the group 2 had higher perinatal complications compared to the group 3. Congenital anomaly was more common in the group 1 than the group 2 (21.9% vs. 11.9%, p