Membrane sweeping vs double-balloon catheter for cervical ripening: a randomized controlled trial

Membrane sweeping is a simple, safe, and cost-effective method to promote spontaneous labor at term. Compared with expectant management, it reduces the need for formal induction of labor and has been shown to be as effective as prostaglandins or oxytocin in achieving vaginal delivery. The double-balloon catheter is a commonly used mechanical method for cervical ripening. However, direct comparative evidence between membrane sweeping and the double-balloon catheter for cervical ripening is currently lacking.

To compare the effectiveness of membrane sweeping vs double-balloon catheter for cervical ripening in term pregnancies.

A randomized controlled trial conducted at a tertiary center (2024-2025), including term pregnancies with intact membranes requiring cervical ripening with a cervix suitable for either membrane sweeping or double-balloon catheter. Exclusion criteria included prior cervical ripening or sweeping and previous cesarean delivery. After informed consent, participants were randomized to membrane sweeping (performed twice, at admission and after 4-6 hours) or double-balloon catheter, inserted for 12 hours. The primary outcome was the change in Bishop score (Δ Bishop score) from baseline to 12 hours postintervention. Secondary outcomes included time to cervical ripening and delivery, oxytocin use, obstetric and neonatal outcomes, pain assessed by visual analog scale, and patient satisfaction. The sample size, powered for noninferiority in Δ Bishop score, required ≥25 participants per group. Analyses were conducted using both intention-to-treat and per-protocol approaches.

Of 114 patients randomized (membrane sweeping: 60; double-balloon catheter: 54), 107 were analyzed per protocol (membrane sweeping: 57; double-balloon catheter: 50). Baseline characteristics and Bishop scores were similar between groups. At 12 hours, median Δ Bishop scores were comparable (2 [1-3] vs 2 [1-3], P=.657). Ripening duration, visual analog scale scores, and satisfaction scales were also similar. Membrane sweeping was associated with lower oxytocin use (63.8% vs 94.3%, P<.001) and a shorter stay in the delivery room (8.9±6.0 vs 12.8±7.8 hours, P=.002). In the per-protocol analysis, delivery within 16 hours was more frequent with membrane sweeping (35.1% vs 16.0%, P=.025), with a similar trend at 20 hours (45.6% vs 28%, P=.06). No differences were observed in tachysystole, delivery within 24 hours, mode of delivery, or other obstetric outcomes.

Membrane sweeping was noninferior to double-balloon catheter in Δ Bishop score, with the additional advantages of reduced oxytocin use and shorter time to delivery-possibly due to its physiological effect. As a low-cost, minimally invasive option, membrane sweeping may be preferable for selected term pregnancies requiring cervical ripening.