Niche development after closure of caesarean uterotomy by conventional double‐suture or modified single‐suture technique (NICUM): A randomized trial

Abstract

Abstract Introduction The aim of the study was to compare two different techniques for closure of the caesarean uterotomy on the occurrence of a caesarean scar niche. Methods The study was a randomized controlled trial performed in a tertiary hospital with inclusion of singleton pregnant women with a scheduled, first caesarean section. We randomized participants to two different uterotomy closure techniques; (1) Conventional double‐suture using a running suture involving the myometrium followed by a running superficial suture or (2) modified single‐suture technique with running alternating deep‐superficial stitches. The primary outcome was the proportion of caesarean scar niches >2 mm deep at 6 months' follow‐up using transvaginal hysterosalinography. Secondary outcomes included residual myometrial thickness and scar niche measurements. Analyses were by intention‐to‐treat. Results We randomized 230 women; 115 in each intervention group. The follow‐up rate was >70% in both groups. Caesarean scar niches >2 mm deep occurred in 42/81 women (52%) after double‐suture versus 35/81 women (43%) after single‐suture closure (risk difference [RD] 8.6% (95% confidence interval [CI] −6.9; 24.2)). Women in the single‐suture group had more additional stitches to the uterotomy closure. The niche was deeper after double‐suture than after single‐suture (RD 0.52 mm (95% CI 0.01–1.02). There were no other differences in ultrasonograpic or maternal clinical secondary outcomes between the two groups. Conclusion We hypothesized a decreased occurrence of caesarean scar niches using a single‐suture technique as compared to double‐suture closure but did not observe a difference in niche occurrence between the two techniques.

Keywords

• caesarean section
• scar niche
• uterine closure