Background: As the number of indications for labour induction continue to increase, the focus has shifted to performing these procedures in an outpatient setting. This study aims to systematically review published data from randomized controlled trials that compare outpatient with inpatient labour induction, to ascertain the role of outpatient labour induction for low-risk pregnancies. Methods: We conducted a systematic review wherein we searched MEDLINE, EMBASE, Biosis Previews®, and International Pharmaceutical Abstracts from inception to January 2020 to identify randomized controlled trials that reported on maternal, fetal and resource-related outcomes following outpatient versus inpatient labour induction. Pooled incidences and mean differences were calculated using random-effects meta-analysis. Risk-of-bias was assessed using the Cochrane Risk of Bias tool. Subgroup analysis was conducted based on the method of induction. Results: Of the 588 records identified, 12 publications, representing nine independent randomized controlled trials conducted in Australia, Europe and North America, were included. These reported on 2615 cases of labour induction (1320 outpatients versus 1295 inpatients). Overall, apart from a higher number of suspicious fetal heart rate tracings [RR = 1.43 (1.10, 1.86)] and a shorter mean length of hospital stay [MD = 282.48 min (160.23, 404.73) shorter] in the outpatient group, there were no differences in delivery method, adverse outcomes or resource-use between the two arms. On subgroup analysis, when comparing the use of balloon catheters in both arms, those induced as outpatients had fewer caesarean deliveries [RR = 0.52 (0.30, 0.90)], a shorter admission-to-delivery interval [MD = 370.86 min (19.19, 722.54) shorter], and a shorter induction to delivery interval [MD = 330.42 min (120.13, 540.71) shorter]. Conclusion: Outpatient labour induction in resource-rich settings is at least as effective and safe, in carefully selected patient populations, when compared with inpatient labour induction. Whether outpatient labour induction results in lower rates of caesarean deliveries needs to be explored further. Trial registration: This systematic review was prospectively registered in Prospero (CRD42019118049).

An amendment to this paper has been published and can be accessed via the original article.

INTRODUCTION: The purpose of this study was to compare clinical and cost outcomes between inpatient and outpatient labor induction. METHODS: A systematic review of randomized controlled trials (RCTs) that compared inpatient vs. outpatient induction was conducted. Four databases were searched for RCTs published in English, which compared any method of outpatient vs. inpatient labor induction. As significant heterogeneity between studies was anticipated, random-effects meta-analysis was conducted. Results were presented as odds ratios (OR) and mean difference (MD) with 95% confidence intervals (95% CI) as appropriate. RESULTS: We identified 695 studies of which 10 representing 7 RCTs (2038 patients) conducted in Australia (n=3), Canada, Portugal, the Netherlands and United States were included in the final analysis. Three RCTs compared induction using balloon catheters, two compared prostaglandins, one compared balloon catheters (outpatient) vs. prostaglandin (inpatient) and one compared outpatient amniotomy vs. inpatient induction using the obstetricians' method of choice. Outpatient vs. inpatient induction was associated with a significant reduction in admission-to-delivery duration [2 studies, 231 patients: MD 11.78 hours (7.09, 16.49)]. There was no difference in use of epidural analgesia [4 studies, 475/863 vs. 454/832, OR 1.04 (0.84, 1.27)], oxytocin [4 studies, 292/643 vs. 269/632, OR 1.143 (0.52, 2.52)], vaginal birth [5 studies, 392/708 vs. 388/697, OR 0.97 (0.70, 1.32)], hyperstimulation [4 studies, 12/643 vs. 9/632, OR 1.27 (0.52, 3.11)] or costs [MD $80.21 (-638.20, 798.61)]. CONCLUSION: Outpatient labor induction is associated with shorter admission-to-delivery duration, with no significant differences in adverse clinical or cost outcomes and may therefore be considered as an alternative to inpatient IOL in low-risk pregnancies.