Does ultrasound-guided intervention during repeat cesarean sections improve uterine scar architecture and reduce the number of scars? A prospective controlled clinical intervention trial.

Purpose To evaluate whether intraoperative ultrasound-guided detection and resection of the uterine scar during repeat/second cesarean can reduce the number of scars and improve uterine scar architecture. Materials and methods A prospective controlled clinical intervention trial was performed with the following groups: control group 1 (CS1-G): first cesarean; control group 2 (CS2-G): second cesarean utilizing the usual procedure and intervention group (Int-G): repeat/second cesarean with intervention. Transvaginal ultrasound scans were performed 6-9 months after each cesarean. Both primary (double scarring rate) and secondary outcomes [deficiency ratio=d/(b+d)] were analyzed. The deficiency ratio describes the thinning of the remaining myometrium (d=residual myometrial thickness) over the "apparent" defect (b=scar depth). Results In total, 124 of the 156 recruited women were examined, eight were excluded from analysis. The double scarring rate decreased from 42.9% (12/28) in CS2-G to 7.1% (2/28) in the Int-G [difference: 35.8%; 95% confidence interval (CI) (13.2, 54.5); P=0.002]. Two-way analysis of variance (ANOVA) revealed a significant difference between CS2-G and the Int-G in the deficiency ratio adjusted for elective/primary cesareans, with thicker remaining myometrium over the scar defect in the Int-G [difference: -0.24; 95% CI (-0.34, -0.15); P<0.001]. Conclusion Ultrasound-guided resection of the uterine scar area during repeat cesareans reduces the scarring rate and improves thickness of the remaining myometrium as detected by ultrasonography 6-9 months postoperatively.