We read with interest the article by Bujold et al. The authors provide a thoughtful and comprehensive synthesis on uterine closure after cesarean delivery, effectively linking surgical technique with the biological foundations of uterine healing. In the spirit of constructive collaboration, we would like to offer several considerations to broaden and contextualize the discussion.

Although historical animal studies and selected modern trials support these principles, large multicenter randomized trials have not consistently demonstrated clear differences in major clinical outcomes between single- and double-layer closures. Similarly, the concept of whether or not to include the decidua in the suture requires clarification, as this cellular layer becomes disrupted or absent in some areas of the uterus at the end of pregnancy. The junctional zone is likely the layer that can be macroscopically identified during surgery as the innermost portion of the uterine wall to be sutured.

These details highlight a persistent challenge in the field: histological and imaging markers of uterine healing do not always correlate with outcomes, such as uterine rupture, fertility, or placenta accreta spectrum (PAS). Rather than weakening the authors’ argument, this underscores the complexity of translating biologically plausible mechanisms into meaningful clinical endpoints and the need for nuanced interpretation of heterogeneous evidence.

The rationale for a 3-layer closure—particularly the goal of restoring serosal integrity—is similarly compelling. However, robust comparative data demonstrating reductions in adhesion formation, improvements in long-term scar architecture, or enhanced reproductive outcomes remain limited.

An important complementary perspective concerns the role of intrinsic vascular anatomy in uterine healing. Certain regions of the lower uterine segment possess limited arterial supply and few collateral systems, which may reduce oxygen delivery ( Figure )—an essential component for vascular growth factor activity, collagen maturation, and myofibroblast function, all of which support wound coaptation after suture absorption. Such a compromised microenvironment may predispose patients to dehiscence and PAS independent of closure technique. Conversely, upper uterine segments incisions with richer anastomotic blood flow may heal more reliably—an appealing, relatively simple solution to prevent large uterine postoperative defect supported by randomized controlled trials. A multicenter randomized trial evaluating this concept is currently underway.

Blood supply for the lower uterine segment

A, Uterine cast. The vascular cast illustrates the 3-dimensional architecture of the uterine and ovarian arterial systems, highlighting their distinct regional perfusion patterns. The uterine arteries (UA) course medially with their characteristic tortuosity before dividing into an extensive, highly anastomosed network that supplies the uterine body and fundus. In contrast, the lower uterine segment—represented here by a relatively avascular oval region corresponding to the typical site of cesarean delivery—receives only sparse collateral branches. This abrupt transition from the minimally perfused lower segment to the richly interconnected arterial plexus just a few centimeters above underscores the physiological rationale for incising the lower uterine segment during cesarean birth. The OAs contribute additional collateral flow through the utero-ovarian arcade, further reinforcing the dense vascular supply of the upper uterus. B, Uterine blood supply. This schematic representation delineates the differential vascular supply of the lower and upper uterine segments. The lower part of the uterine segment, which receives blood supply by the CVA, is predominantly supplied by the descending branch of the uterine artery, receiving only limited collateral input—approximately 20%—from the vaginal arterial pedicle (VA). In contrast, the upper segment of the lower uterus (1, depicted in green ) benefits from a far more robust perfusion pattern, with a fully developed anastomotic network supplied by 100% of the ascending uterine arterial branches. This clear distinction between the sparsely anastomosed cervicovaginal territory and the richly interconnected upper segment underscores the functional compartmentalization of uterine segment blood flow and helps explain the differences in oxygen delivery observed after surgical incisions in the lower and upper uterine segment sectors. Modified with permission from Robinson.

BL , bladder; CE , cervix; CVA , cervicovaginal artery; OA , ovarian artery; UA , uterine artery; VA , vaginal artery.

Palacios-Jaraquemada. Vascular insights in cesarean closure. Am J Obstet Gynecol 2026.

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