OP25.07: Ultrasound evaluation of the cesarean scar: comparison between one and two layer uterotomy closure

Objectives: To compare the residual myometrial thickness and the size of the cesarean scar defect after oneand two layer uterotomy closure. Methods: From July 2010 a continuous two-layer uterotomy closure technique replaced a continuous one-layer technique after cesarean delivery at the Department of Obstetrics and Gynecology at Aarhus University Hospital. A total of 149 consecutively invited women (68 women with one-layer and 81 women with two-layer closure) had their cesarean scar examined with 2D transvaginal sonography (TVS) 6–16 months post partum. Inclusion criteria were non-pregnant women with one previous elective cesarean, no post-partum uterine infection or uterine re-operation, and no type 1 diabetes. Scar defect width, depth, and residual myometrial thickness were measured on the sagittal plane, and scar defect length was measured on the transverse plane. Results: The median residual myometrial thickness was 4.6 mm (interquartile range (iqr) ± 3.1) after one-layer closure and 5.8 mm (iqr ± 3.7) after two-layer closure (P = 0.04). A scar defect was visible in 66/68 women (97%) with one-layer closure, and 78/81 women (96%) with two-layer closure, respectively. Median defect width was 6.8 mm (iqr ± 4.1) after one-layer compared to 5.6 mm (iqr ± 2.9) after two-layer closure (P = 0.01). No significant differences were found in defect height and length between women with oneand two-layer closure. Conclusions: Two-layer closure of the uterotomy significantly increases residual myometrial thickness and decreases defect width. Results do not prove but imply increased scar strength after two-layer closure.