Abstract
To compare single- versus double-layer uterine closure after cesarean delivery on cesarean scar outcomes, with uterine rupture or dehiscence in a subsequent pregnancy as the primary outcome, and niche incidence, niche depth, and residual myometrial thickness as secondary outcomes, using a time-stratified meta-analysis of randomized controlled trials.
PubMed, Cochrane CENTRAL, Scopus, and Web of Science were searched from database inception to November 10, 2025, using terms related to cesarean delivery and single- or double-layer uterine closure.
Randomized controlled trials involving women aged ≥18 years undergoing cesarean delivery that directly compared single-layer versus double-layer uterine closure and reported at least one outcome of interest (niche incidence, niche depth, residual myometrial thickness, or uterine dehiscence).
Two reviewers independently screened records, extracted data, and assessed risk of bias using Cochrane RoB 2. Random-effects meta-analyses were performed using risk ratios for dichotomous outcomes and mean differences for continuous outcomes, stratified by follow-up interval (6 weeks, 3 months, 6 months, 12 months); sensitivity analyses addressed heterogeneity. Comparisons were performed within each follow-up interval (same timepoint in both groups), to examine whether the between-technique effect differs by follow-up time.
After trustworthiness assessment, twenty-one randomized controlled trials (8564 women) were included. The primary outcome, uterine rupture or dehiscence in a subsequent pregnancy, did not differ significantly between techniques (risk ratio 1.97, 95% confidence interval 0.66–5.94). No significant differences were found in niche incidence at any time point. Double-layer closure was associated with thicker residual myometrial thickness at 6 weeks (mean difference −1.07 mm, 95% confidence interval −1.34 to −0.80) and 6 months (mean difference −1.16 mm, 95% confidence interval −1.79 to −0.54). Single-layer closure was associated with shallower niche depth at 3 months (mean difference −1.29 mm, 95% confidence interval −1.77 to −0.80).
Double-layer uterine closure yields greater residual myometrial thickness but does not reduce niche incidence or risk of uterine dehiscence compared with single-layer closure. The clinical significance of improved sonographic markers remains uncertain, underscoring the need for future trials focused on long-term clinical outcomes.