Outpatient or Inpatient Setting for Cervical Ripening Before Induction of Labour: An Individual Participant Data Meta-Analysis

Abstract

Background: The optimal methods and settings for induction of labour (IOL) in terms of effectiveness, safety, and women's experience are still not elucidated. Objective: To compare the effectiveness and safety of outpatient versus inpatient cervical ripening settings for IOL. Search Strategy: MEDLINE, Embase, Emcare, CINAHL Plus, Scopus, Cochrane Library, WHO ICTRP and clinicaltrials.gov from inception to July 2024. Selection Criteria: Randomised controlled trials, viable singleton gestation, no language restrictions, all the published and unpublished data. Data Collection and Analysis: An individual participant data meta-analysis. Main Results: Eleven out of 18 (61.1%) eligible RCTs shared IPD, totalling 2593 pregnant individuals undergoing IOL (62.2% of all participants in the published RCTs). Among the shared RCTs, four used balloon catheters alone in both groups. Three RCTs compared outpatient balloon catheter with inpatient balloon catheter plus oxytocin. Another three RCTs compared outpatient balloon catheter to inpatient vaginal dinoprostone. One RCT used Dilapan-S in both groups. No trials evaluating outpatient use of vaginal prostaglandins were identified. Vaginal birth (11 RCTs, 2584 women, 67.8% vs. 70.2%, aOR 0.95, 95% CI 0.70; 1.30), composite perinatal outcome (9 RCTs, 2525 women, 11.1% vs. 11.7%, aOR 0.93, 95% CI 0.75; 1.16) and composite maternal (10 RCTs, 2480 women, 14.3% vs. 15.4%, aOR 0.89, 95% CI 0.65; 1.20) outcome did not differ between outpatient and inpatient groups. The outpatient group had a lower risk of acidosis, more epidural analgesia, and more oxytocin. There were no perinatal deaths in either group. Conclusions: Overall effectiveness, perinatal and maternal safety are comparable between outpatient setting cervical ripening with a mechanical method and inpatient with any method. Trial Registration: PROSPERO: CRD42022313183.