Exploring the Optimal Intertwin Delivery Interval for Vaginal Delivery.

The effect of prolonged intertwin delivery interval (IDI) is not well studied. This work aimed to assess the inflection point for Cesarean delivery (CD) and associated adverse maternal and neonatal outcomes. This was a retrospective cohort study at a single tertiary care center. The study included women with twin pregnancies in 2010-2019 who reached the second stage of labor, and assessed the most predictive cutoff for CD using Youden J statistic and compared adverse maternal and neonatal outcomes between short and prolonged intertwin delivery intervals. A total of 461 gravidas reached the second stage of labor and were included in the study. Using the ROC curve and Youden J statistic, the IDI cutoff was set at 15 min (80% sensitivity, 75% specificity, p < 0.001), with 312 women in the short and 149 in the prolonged IDI groups. Women in the prolonged IDI group were less likely to deliver the second twin vaginally (75.8% vs. 93.3%, p < 0.001). Postpartum hemorrhage (PPH) (39.1% vs. 24.7%, p = 0.01), and placental abruption (4% vs. 1%, p = 0.03) were more likely to occur in the prolonged IDI group. An increased rate of neonatal acidemia and low 5-min Apgar score were also found in the prolonged IDI group (15.7% vs. 4.3%, P = 0.01, 9.7% vs. 3.5%, p = 0.008; respectively). IDIs of more than 15 min are associated with increased risk of adverse maternal and neonatal outcomes. These findings should be used for counseling and managing twin pregnancies attempting vaginal delivery.