Long‐term gynecological symptoms and ultrasound and reproductive outcomes after monofilament vs multifilament uterine closure at Cesarean delivery: secondary analysis of randomized controlled trial

OBJECTIVE: To evaluate long-term gynecological symptoms and reproductive and ultrasound outcomes among women originally enrolled in a randomized controlled trial (RCT) comparing monofilament and multifilament sutures for uterine closure after Cesarean delivery. METHODS: This was a secondary analysis of a RCT including women who underwent Cesarean delivery, who were originally assigned to monofilament or multifilament absorbable sutures for uterine closure. In this secondary analysis, participants were contacted 4-6 years after delivery and invited to a follow-up evaluation, comprising a clinical interview and a voluntary transvaginal ultrasound examination. The primary outcome was the presence of postmenstrual spotting at long-term follow-up. Secondary outcomes were other gynecological symptoms, reproductive outcomes and ultrasound outcomes. Analyses were performed according to the original randomized allocation. Effect estimates are reported as relative risk (RR) with 95% CI. RESULTS: Of the 300 women included in the original RCT, 117 (39.0%) were included in the long-term follow-up analysis, comprising 51 in the monofilament group and 66 in the multifilament group. There was no significant difference in the primary outcome of postmenstrual spotting between the monofilament and multifilament groups (23.5% vs 22.7%; RR, 1.04 (95% CI, 0.53-2.01)). Similarly, no significant differences were observed between groups for other gynecological symptoms. Ultrasound data were available for 21 women, of whom 13 had a Cesarean-scar defect. The overall prevalence of Cesarean-scar defects was similar between groups, although defects ≥ 4 mm were more frequent in the multifilament group (RR, 0.42 (95% CI, 0.18-0.97); P = 0.04). Most reproductive outcomes, including infertility and pregnancy outcomes among women who conceived, were comparable between groups. However, subsequent pregnancy occurred more frequently in the monofilament group (29.4% vs 12.1%; RR, 2.43 (95% CI, 1.12-5.27)). CONCLUSIONS: In this long-term follow-up of a RCT, monofilament and multifilament sutures for uterine closure were associated with similar long-term gynecological symptoms. Differences observed in selected ultrasound and reproductive outcomes should be interpreted cautiously because of the limited sample size and exploratory nature of these analyses. Further studies are needed to better evaluate the potential impact of suture material on long-term reproductive outcomes and sonographic Cesarean-scar characteristics. © 2026 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.