Membrane sweeping at term to promote spontaneous labor and reduce the likelihood of formal labor induction for prolonged pregnancy, in South Asia and the world: A meta-analysis

Background: Membrane sweeping promotes the spontaneous onset of labor, reducing the need for formal labor induction. In addition to the safety profile, membrane sweep is a cost-effective measure in a low-resource setting like South Asia.

Objectives: To the best of our knowledge, previous reviews and meta-analyses have not explored the timing and frequency of membrane sweeping or its association with the period of gestation (POG) and parity. Additionally, the results should be interpreted with caution due to the inclusion of older studies and the analyses conducted regardless of ethnicity in previous literature. We addressed these gray areas in the current study to fill the research gap.

Search strategy: We searched PubMed, Google Scholar, Science Direct, and Cochrane Reviews. Study selection was performed using the semi-automated tool Rayyan.

Selection criteria: The selection criteria for this study encompassed the inclusion of randomized controlled trials (RCTs) published in English between January 2010 and May 2023, with accessible full-text articles. The focus was on low-risk pregnant women carrying a single fetus in a cephalic presentation at term (37-42 weeks) gestation, confirmed by reliable methods. Essential data for relative risk (RR) and 95% confidence interval (CI) calculation must be present.

Data collection and analysis: The Cochrane risk-of-bias (RoB2) tool and funnel plots were used to assess bias. Review Manager (RevMan) 5.4 version was used for analysis. The Mantel-Haenszel statistics and random effects were used to calculate the overall effect of risk ratio with a 95% confidence interval. Study heterogeneity was calculated using the I² statistic. Two subgroups were used in the analysis: South Asia and the rest of the world.

Main results: A total of 13 RCTs with 2599 participants were analyzed. Overall, membrane sweep effectively reduced formal IOL with an effect size of 2.43 (95% CI: 1.51-3.91). It also promoted spontaneous labor with an effect size of 1.71 (95% CI: 1.15-2.55). In the South Asian subgroup, membrane sweeping significantly promoted the spontaneous onset of labor with an overall effect of 1.85 (95% CI: 1.37-2.51), and in the rest of the world subgroup, membrane sweeping significantly reduced formal labor induction with an overall effect of 1.93 (95% CI: 1.33-2.82). The pooled effects were significant in mulipara with a POG ≥40 W in the South Asian subgroup.

Conclusions: Membrane sweeping effectively reduces the need for formal labor induction and promotes spontaneous labor. This may be particularly relevant in South Asian populations where a disproportionate ethnic contribution to stillbirth rates is noted. Due to the limited number of RCTs addressing the factors and study methodology heterogeneity, we had limited data in some subgroup analyses. Therefore, we encourage more RCTs and meta-analyses on POG, parity, timing and frequency of membrane sweeping, and ethnic differences.