Clinical outcomes of first trimester discordant twins

Song, Seung Eun; Ko, Ok Jin; Cho, Hyun Ji; Seo, Eun Sung; Jung, Kyung Lan; Choi, Suk Joo; Oh, Soo young; Roh, Cheong Rae; Kim, Jong Hwa

Abstract

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 > or =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<0.001). However, FGR rate was higher in the group 2 than the group 1 (32.3% vs. 71.8%, p<0.01). Congenital anomaly, FGR and FDIU were more common in the group 1 compared to the group 3 (21.9% vs. 3.5%, p<0.001, 32.3% vs. 9.1%, p<0.01, 6.3% vs. 1.0%, p<0.05, respectively).
CONCLUSIONS
First trimester discordant twins have an increased risk of congenital anomaly, FGR and FDIU, and therefore, they should be regarded as a high-risk pregnancy likewise second or third trimester discordant twins.