Inter-twin delivery interval and outcome of the second twin: A retrospective study

To examine the association between the inter-twin delivery interval and outcome of the second twin in a large sample.

This was a retrospective study at a single tertiary center between the years 2011 and 2021. The study included diamniotic twin pregnancies at ≥24 weeks of gestation that underwent a trial of vaginal delivery. A total of 1808 cases of twin pregnancies were included in the study. Cases were grouped according to inter-twin delivery interval of ≤15 min (n = 1676) or >15 min (n = 132). The neonatal outcome of the second twin was compared between the groups. In addition, we evaluated possible factors affecting the inter-twin delivery interval.

Umbilical cord pH and base deficit were significantly lower and higher, respectively, for the second twin in the prolonged interval group; however, no difference was shown concerning neonatal composite outcome. In addition, a prolonged inter-twin interval was significantly associated with maternal age, body mass index, gestational age, labor induction, rupture of membranes duration, intrapartum fever, nighttime shift, birth weight of the second twin, twin birth weight ratio, and discordancy >20%. On the other hand, a short inter-twin interval was significantly associated with monochorionicity and neonatal intensive care unit admission.

Our study showed no significant effect of inter-twin delivery interval on the composite outcome of the second twin. However, a prolonged inter-twin interval was associated with lower umbilical cord pH and higher base deficit.