Early versus late amniotomy during twin labor

This study evaluates whether timing of amniotomy affects labor characteristics and maternal and neonatal outcomes in twin deliveries.

This retrospective study was conducted at a single academic medical center and included dichorionic diamniotic (DCDA) twin pregnancies with a normal anomaly scan and a vertex-presenting leading twin, delivered over a 7-year period. The cohort was divided into two groups: early amniotomy (performed at cervical dilation ≤3 cm) and late amniotomy (performed at >3 cm cervical dilation). Exclusion criteria included monochorionic twin pregnancies and planned elective cesarean deliveries. Maternal demographics, delivery characteristics, and neonatal outcomes were compared between groups.

Of 51 592 deliveries, 1196 were twins; 565 DCDA pregnancies met the inclusion criteria (early n = 279; late n = 286). Groups were similar in age, body mass index (kg/m²), comorbidities, and gestation. Nulliparity and intrapartum cesarean rates were more common in the early amniotomy group (56.6% vs. 29.4%; P < 0.001, 24.4% vs. 9.8%; P < 0.001, respectively). Induction and augmentation rates, rupture-to-delivery interval, second stage duration, intrapartum fever, and meconium were similar. Neonatal outcomes, including birthweight, 5-min Apgar <7, neonatal intensive care unit admission, and composite morbidity were comparable. On adjusted analysis, early amniotomy (adjusted odds ratio [aOR] 1.84; 95% confidence interval 1.09-3.1), nulliparity (aOR 5.60; 3.17-9.87), and previous cesarean (aOR 3.94; 1.32-11.77) increased cesarean risk, whereas epidural was protective (aOR 0.40; 0.24-0.67).

In DCDA twin labor, early amniotomy (≤3 cm) is associated with increased intrapartum cesarean, despite similar durations of labor and neonatal outcomes. Amniotomy timing should be individualized, with caution against routine early rupture.