Two-layer interrupted versus two-layer continuous sutures for preventing cesarean scar defect: a randomized controlled trial.

Background: Cesarean scar defects can lead to long-term complications, such as cesarean scar disorders, cesarean scar pregnancy, and the risk of uterine scar dehiscence and rupture in subsequent pregnancy. However, the optimal closure technique to prevent the development of cesarean scar defects (CSD) remains unclear. Therefore, this study aimed to explore whether two-layer interrupted versus two-layer continuous sutures could prevent the formation of CSD.

Methods: A randomized controlled trial was conducted in a single university hospital in Japan. We recruited pregnant women with ≥ 20 primary or previous cesarean sections. Participants were randomly assigned to either a two-layer interrupted or a two-layer continuous suture group. Residual myometrial thickness (RMT) and the depth of CSD were measured using sonohysterography, 6-8 months post-cesarean section. In addition, the rate of severe CSD, defined as a loss of over 50% of the myometrium, was examined.

Results: Of the 220 study participants, 43 dropped out; 89 in the interrupted group and 88 in the continuous group underwent sonohysterography. No significant difference in RMT was observed in the interrupted and continuous groups (median 8.1 [interquartile range, 6.2-9.9] mm and 7.9 [4.6-10.3] mm, respectively). However, the incidence of severe CSD in the interrupted group was significantly lower than that in the continuous group (2% versus 22%, p < 0.0001). Multivariate logistic regression analysis revealed that the factors contributing to developing severe CSD were interrupted suture (odds ratio [OR]: 0.04, 95% confidence interval [95%CI]: 0.006-0.281, p = 0.0011), the difference in myometrial thickness between the fundal and cervical sides at the center of the uterine wound before suturing (OR: 1.65, 95%CI: 1.144-2.367, p = 0.0072), and retroversion of the uterus at 6-8 months after cesarean section (OR: 3.42, 95%CI: 1.074-10.946, p = 0.0374).

Conclusion: This study suggested that two-layer interrupted sutures are superior to two-layer continuous sutures in preventing the development of severe CSD.

Trial Registration: Clinical trial identification number: University Hospital Medical Information Network registration code, UMIN000040601. URL of the registration site: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046334 .