OC22.04: Twin actual birthweight discordance and adverse pregnancy outcome: the STORK multiple pregnancy cohort

Abstract

TTTS. Methods: A retrospective study of all twin pregnancy births of known chorionicity from a large regional cohort of 9 hospitals over a ten year period. Ultrasound data was matched to hospital delivery records and a mandatory national register for perinatal losses (CMACE). Cumulative fetal and perinatal loss rates for MC and DC twins from 14 to 26 weeks gestation were analysed using Kaplan-Meier survival curves to assess the difference in mortality between MC and DC twins. Results: 3133 twin pregnancies (599 MC and 2534 DC) were included in the analysis. The total fetal loss rate in MC and DC twins were 6.3% (75/1198) and 0.9% (44/5068), respectively (OR 0.14, 95% CI 0.09 to 0.20). The cumulative rate of loss in MC twins rose significantly from 0.5% at 14 weeks’ gestation up to a plateau of 6.3% at 24–26 weeks’ gestation, whereas there was no significant change in DC pregnancy loss rate (0.5%) over this period. Kaplan Meier curves for MC and DC twins were statistically different (log-rank test < 0.05). Conclusions: Early perinatal loss rates before 26 weeks are significantly higher in MC compared to DC twins. Cumulative fetal loss rate before 26 weeks’ gestation in MC twins has almost halved compared to the rates available in the published literature a decade ago. Early detection and prompt treatment of complications in MC twins is likely to have contributed to this improvement in twin pregnancy outcomes.