Foley catheter versus vaginal dinoprostone for induction of labour in women with one previous caesarean birth: the MEDICS randomised-controlled trial

Rising global caesarean section (CS) rates carry significant maternal and perinatal implications. Vaginal Birth After Caesarean (VBAC) is endorsed to reduce repeat CS, but safe induction of labour (IOL) modalities for Trial of Labour After Caesarean (TOLAC) remain poorly established. Vaginal Prostaglandin (PG)-based agents risk uterine hyperstimulation and uterine rupture. Mechanical induction (MI) with Foley catheter balloon (FCB) may lower this risk, yet no comparative trials exist in this population. An open-label randomised controlled trial was conducted between 2019 and 2022 at the National University Hospital, Singapore. Term multigravidas with one prior lower-segment CS requiring IOL and an unfavourable cervix (Modified Bishop Score [MBS] < 6) were randomised 1:1 to MI or 3 mg vaginal dinoprostone tablets. Major exclusions included ≥ 2 CS, non-lower-segment incisions, major uterine surgery, and contraindications to vaginal birth. The primary outcome was proportion achieving MBS ≥ 6 within 24 h. Secondary outcomes included VBAC rate, time to labour and delivery, oxytocin and epidural use, intrapartum and peripartum complications, and maternal satisfaction. Kaplan-Meier survival analysis was applied for time-to-event outcomes with censoring for failed IOL. (ClinicalTrials.gov NCT03471858; https://clinicaltrials.gov/study/NCT03471858 ) Forty-four women were randomised (MI n = 21; PG n = 23) with comparable baseline characteristics. MI achieved significantly higher rates of MBS ≥ 6 within 24 h (76.2% vs. 43.5%, RR 1.75 [95% CI 1.04–2.96], p = 0.027). Median times to delivery (24.2 h vs. 19.0 h, p = 0.140) and established labour (15.8 h vs. 12.8 h [ p = 0.947]) were similar. Intrapartum complications were significantly fewer with MI (RR 0.24 [95% CI 0.06–0.99], p = 0.023). VBAC success was comparable (33.3% vs. 39.1% [ p = 0.690]). Oxytocin augmentation, analgesia use, peripartum complications, and satisfaction scores were similar, with > 90% survey response rates. No uterine ruptures occurred. MI with FCB achieved superior cervical ripening and fewer intrapartum complications than PG in multigravidas with one prior CS, without prolonging labour or worsening delivery outcomes. These findings provide a preliminary signal supporting the efficacy of FCB as an alternative to prostaglandin for IOL in this population. ClinicalTrials.gov: https://clinicaltrials.gov/study/NCT03471858 on 13th March 2018.