The optimal cutoff for intertwin delivery interval: A retrospective cohort study

To determine the cutoff of intertwin delivery intervals (IDIs) as a predictor for neonatal acidemia.

This retrospective cohort study was conducted at a single tertiary care center. Women attempting vaginal delivery of twins between 2010 and 2019 and who reached the second stage of labor were included. The cutoff point for prolonged IDI was established using a receiver operating characteristic (ROC) curve and Youden's J statistic. Maternal and neonatal outcomes were compared between short and prolonged IDI cohorts.

A total of 461 women were included in the study. A cutoff time of 10 min was found to be the best predictor for neonatal acidemia (arterial cord pH ≤ 7.1), with a sensitivity of 90% and a specificity of 59%. Second twins delivered more than 10 min after the first twin were more likely to be acidemic and to have a 5-min Apgar score of 7 or less (13.5% vs 3.3%, P = 0.01, and 8.4% vs 3.2%, P = 0.02, respectively). An IDI of more than 10 min was also associated with increased rate of cesarean delivery and placental abruption (13.5% vs 0.8%, P < 0.001, and 3.4% vs 0.8%, P = 0.047, respectively). No other adverse maternal or neonatal outcomes were statistically significant between cohorts.

An IDI of more than 10 min is associated with a higher risk for neonatal academia, with a low 5-min Apgar score, and higher cesarean delivery and placental abruption rates. These findings provide insights that are valuable when counseling and managing twin pregnancies attempting vaginal delivery. Interventions aimed at shortening the IDI should be considered to prevent adverse neonatal outcomes.