Mini Commentary

DOI: 10.1111/1471-0528.13095 www.bjog.org

Closure of uterus and the risk of uterine rupture S Roberge & E Bujold Faculty of Medicine, Universite Laval, Laval, QC, Canada Linked article: This is a mini commentary on Hesselman S. To view this article visit http://dx.doi.org/10.1111/ 1471-0528.13015. Published Online 7 October 2014. In a large cohort study including more than 7600 women with previous caesarean section, Hesselman et al. observed a similar rate of uterine rupture in women with a single-layer closure compared with women with a double-layer closure of the uterus at previous caesarean section (adjusted relative risk 1.13; 95% confidence interval [95%] 0.75–1.70). (Hesselman et al. BJOG 2014; doi: 10.1111/1471-0528.13015) This finding is in agreement with a recent meta-analysis showing no significant difference between the two types of closure (odds ratio [OR] 1.17; 95% CI 0.66–4.44). (Roberge et al. Int J Gynaecol Obstet 2011;115:5–10). There is therefore accumulating observations suggesting a minor role, if any, for the number of layers used for uterus closure on the risk of uterine rupture in the next pregnancy. However, other aspects of uterus closure have to be closely evaluated. The latter meta-analysis suggests that a locked single-layer closure could be related to uterine rupture (OR 4.96; 95% CI 2.58–9.52), which is in agreement with another meta-analysis of randomised trials showing that locking a single-layer

Figure 1. Including the inner side of the uterine wall (endometrium) into the suture leads to impaired scar healing and isthmocele.

can lead to a thinner residual myometrium thickness evaluated by ultrasound after caesarean (Roberge et al. Am J Obstet Gynecol 2014 in press). There are at least two potential explanations beyond such association: it is possible that the locked suture, by being more haemostatic, can cause a strangulation of the scar tissue and lead to weaker healing. It is also possible that the weakness of the scar is secondary to the fact that this technique is usually performed with inclusion of the inner part of the uterine wall (decidua/endome-

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trium) in the scar tissue (Figure 1). In several animal models, Poidevin demonstrated that suturing the complete thickness of the uterus, including the endometrium, was associated with inclusions of endometrial tissue in the scar, resulting in scar defects several weeks or months later (Poidevin. Cesarean section scars. Springfield [IL]: Charles C. Thomas Publisher; 1965). Beside the incomplete healing and the increased risk of uterine rupture, another multicentre case–control study reported that including the inner side of the uterine wall

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Mini Commentary

(decidua/endometrium) into the scar with a continuous suture, was associated with an increasing rate of placenta accreta in women with placenta praevia, independently of the number of layers used for uterus closure (Sumigama et al. BJOG 2014;121:866–74). Therefore, the cumulative evidence suggests that continuous suture with inclusion of the inner side of the uterine wall (decidua/endometrial layer) at the time of caesarean section is associated

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with impaired uterine scar evaluated by ultrasound, and with potential long-term consequences such as placenta accreta. Original works from our group (Bujold et al. Am J Obstet Gynecol 2002;186:1326–30; Bujold et al. Obstet Gynecol 2010;116:43–50) suggest a significant increase of uterine rupture with single-layer closure, perhaps related to the fact that the single-layer closure typically used in North America included the full uterine wall and its inner side

into the scar. Future comparative studies, including observational and randomised trials, should focus not necessarily on the number of layers at the time of caesarean but on the inclusion or exclusion of the endometrium in the first layer.

Disclosure of interests There are no conflicts of interest to disclose. &

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