Outcome prediction in monochorionic diamniotic twin pregnancies with moderately discordant amniotic fluid

OBJECTIVE: To identify predictors of twin-to-twin transfusion syndrome (TTTS) and selective intra-uterine growth restriction (sIUGR) in monochorionic diamniotic twin pregnancies with moderate amniotic fluid discordance (mAFD). METHODS: Monochorionic twins with mAFD (n = 45; gestational age range 15-29 weeks) were assessed for severity of fluid discordance, fetal growth discordance and fetal cardiac dysfunction and followed longitudinally. A prediction algorithm was constructed for TTTS and sIUGR and validated in an unrelated cohort (n = 52). RESULTS: Cardiac dysfunction could not predict TTTS nor sIUGR. Twins with a fluid discordance >/= 3.1cm below 20 weeks of gestation had a risk of TTTS of 85.7%. Sensitivity for TTTS was nevertheless only 55%. Intertwin weight discordance >/= 25% had 63% sensitivity and 76% specificity for sIUGR without TTTS. CONCLUSION: Outcome of monochorionic diamniotic twins with mAFD remains unpredictable yet high and low risk subgroups for TTTS can be identified based on severity of fluid discordance and gestational age. Copyright (c) 2010 ISUOG. Published by John Wiley & Sons, Ltd.status: publishe