Ultrasound evaluation of uterine incision healing after cesarean delivery – a randomized controlled study of one-versus two-layer closure

Abstract

Prior studies have suggested improved outcome with two-layer (2L) versus one-layer (1L) closure of the hysterotomy at cesarean delivery. Scar thickness has been shown to be an indicator of scar healing and strength. The purpose of this study was to evaluate by ultrasound the uterine scar thickness (UST) after 1L or 2L closure in women undergoing primary cesarean delivery. 30 patients undergoing primary cesarean delivery were randomized to 1L or 2L closure of the hysterotomy. 1L closure consisted of continuous, locking, delayed absorbable suture; 2L added a second continuous imbricating layer. Evaluation of UST was assessed by ultrasound at 48 hours, 2 weeks, and 6 weeks postpartum. Hysterotomy closure and ultrasound evaluation were performed by the investigators and trained MFM specialists under a standardized protocol. Data were analyzed using Chi square, Student's t-test, and repeated measures ANOVA as appropriate with p < 0.05 considered significant. There were no significant differences in demographics (including parity and gestational age) or intrapartum characteristics (intrapartum fever, bleeding, operative time, additional sutures). Postpartum follow-up compliance was 79.4% and UST was visualized in 98.2% of attempted measurements. There were no differences between closure type and UST (see Fig.). Repeated measures ANOVA revealed significant variation in UST over time (p<0.001), which was not significantly different between surgical techniques (p=0.97). The process of uterine healing can be successfully monitored non-invasively by ultrasound. Scar thickness diminishes progressively following either mode of hysterotomy closure. No difference in UST between closure technique was detected.