OC13.07: Optimal delivery timing for uncomplicated twin pregnancies

The objective of this study was to evaluate the risk of adverse neonatal outcome according to timing of delivery in twins with a gestational age of 37 weeks or more and determine the optimal timing of delivery in uncomplicated twin pregnancies. This retrospective study enrolled uncomplicated Korean twin pregnant women who delivered after 37 weeks of gestation from 2015 to 2021. Women diagnosed with hypertension or diabetes mellitus (DM) prior to pregnancy, those experiencing maternal complications such as gestational hypertension or gestational DM, placenta previa or placental abruption, and those with twin birthweight abnormalities (birthweight of any twin below the 10th percentile or discordance of 20% or more) were excluded from the study. The primary outcome was composite neonatal morbidity including the followings: transient tachypnea, respiratory distress syndrome, hypoglycemia, the use of ventilator and nasal cannula within 7 days after birth. Adverse outcomes in twins were analysed using either individual twins or twin pairs as a case. Logistic regression was applied to calculate the odds ratios of adverse outcomes based on the gestational week at the time of delivery. Out of 25,698 women who delivered at or beyond 37 weeks of gestation, 13,502 women were finally included in the study. In the multivariate analysis, when compared to deliveries at 37 weeks of gestation, the composite morbidity was lower for twin deliveries at both 38 weeks (adjusted odds ratio (aOR), 0.697; 95% Confidence interval (CI), 0.637-0.762) and 39 weeks (aOR, 0.526; 95% CI, 0.417-0.663) of gestation. For deliveries after 40 weeks, the risk of composite morbidity was not significantly different from deliveries at GA 37 weeks (aOR, 0.63; 95% CI, 0.389-1.021). In uncomplicated twin pregnancies, delaying the delivery timing even within the full-term periods is suggested, with appropriate fetal surveillance and personalised consideration of both maternal and fetal conditions.