De Novo Isthmocele Formation After Cesarean Delivery in Uterus Transplant Recipients

To determine the incidence of cesarean scar defect (isthmocele) formation for uterus transplant (UTx) recipients in the setting of immunosuppression and required cesarean deliveries.

Retrospective pilot study with illustrative case series.

Two tertiary-care uterus transplantation programs representing nearly half of uterus transplant cases worldwide.

Nineteen UTx recipients who underwent at least 1 cesarean delivery using their transplanted uterus, who desired a second pregnancy, and who had postpartum transvaginal ultrasound imaging available.

Uterus transplantation followed by embryo transfer and planned cesarean delivery, with routine postoperative imaging surveillance.

The primary outcome was the presence of a postpartum isthmocele on transvaginal ultrasound, defined as a wedge-shaped myometrial defect at the site of an earlier hysterotomy. Six of 19 patients (31.6%) showed imaging findings consistent with an isthmocele. The mean gestational age at delivery was 35 4/7 weeks. No association was identified between earlier obstetric complications and subsequent isthmocele formation in our small cohort. Among affected patients, 66.7% received donor uteri with cesarean delivery before donation. Representative cases highlight a clinical spectrum of presentations in this context and illustrate the underlying clinical complexity when isthmocele is encountered during a high-stakes fertility journey.

UTx recipients in our cohort showed isthmocele formation comparable with that reported in non-transplant populations. These findings suggest that cesarean scar healing may not be significantly impaired in the transplanted uterus even despite exposure to immunosuppressive therapy. Recognition of isthmocele in this population is clinically relevant, as it may guide transplant donor characteristics and impact UTx fertility treatment. Larger prospective studies are warranted to further define risk factors and optimize surgical and reproductive outcomes.