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.

Continuous vs intermittent induction of labor with oxytocin in nulliparous patients: a randomized controlled trial

BACKGROUND

Oxytocin is considered the drug of choice for the induction of labor, although the optimal protocol and infusion duration remain to be determined.

OBJECTIVE

This study aimed to assess whether the duration of oxytocin infusion increases 24-hour delivery rates and affects the length of time-to-delivery and patient's experience.

STUDY DESIGN

A randomized controlled trial was performed at a single tertiary medical center, between January 1, 2020 and June 30, 2022. Nulliparous patients with a singleton pregnancy at a vertex presentation and a Bishop score ≥6 were randomly assigned to receive either continuous (16 hours, with a 4 hours pause in between infusions) or intermittent (8 hours, with a 4 hours pause in between infusions) oxytocin infusion, until delivery. In both groups, infusion was halted when signs of maternal or fetal compromise were observed. Randomization was conducted with a computer randomization sequence generation program. The primary outcome was delivery within 24 hours from the first oxytocin infusion and the secondary outcome included time-to-delivery, mode of delivery, and additional maternal and neonatal outcomes. Seventy-two patients per group were randomized to reach 80% statistical power with a 20% difference in the primary outcome according to previous studies.

RESULTS

A total of 153 patients were randomized, 72 to the continuous oxytocin infusion group and 81 to the intermittent infusion group. The total oxytocin infusion time was similar between the groups. Patients in the continuous arm were more likely to deliver within 24 hours from oxytocin initiation (79.73% vs 62.96%, P<.05), and had a shorter oxytocin-to-delivery time interval, compared with patients receiving intermittent treatment (9.3±3.7 hours vs 21±11.7 hours, P<.001). Furthermore, time from ruptured membranes to delivery was shorter (9.3±3.7 hours vs 21±11.7 hours; P<.0001) and chorioamnionitis was less frequent (9.46% vs 21%; P<.05) in the continuous compared with the intermittent arm. Cesarean delivery rate was 20% in both groups (P=.226). There was no difference in postpartum hemorrhage, or adverse neonatal outcomes between the groups. Patients receiving continuous oxytocin infusion were more satisfied with the birthing experience.

CONCLUSION

Continuous infusion of oxytocin for labor induction in nulliparous patients with a favorable cervix may be superior to intermittent oxytocin infusion, because it shortens time-to-delivery, decreases chorioamnionitis rate, and improves maternal satisfaction, without affecting adverse maternal or neonatal outcomes.