Abstract Objective The optimal embryo transfer strategy for women with a history of cesarean delivery (CD) remains highly controversial. CD causes uterine microenvironmental damage, especially cesarean scar niche formation and chronic low‐grade inflammation, both of which severely impair endometrial receptivity. Supraphysiological hormones during controlled ovarian stimulation (COS) further exacerbate these harmful conditions, creating a “double hit” that compromises implantation. This study aimed to compare the reproductive outcomes of fresh embryo transfer (fresh ET) versus a “freeze‐all” frozen‐thawed embryo transfer (FET) strategy in this specific population. Methods A large‐scale retrospective cohort study was conducted including women with a history of a single CD undergoing their first or second in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycle. To minimize selection bias and balance baseline and embryological covariates, a 1:1 propensity score matching (PSM) was performed. The primary outcome was the live birth rate (LBR) per transfer. Results Following PSM, 412 well‐matched pairs ( n = 824 cycles) were analyzed. The FET group was found associated with a significantly higher LBR compared to the fresh ET group (42.2% vs 33.5%; odds ratio OR 1.45, 95% confidence interval CI: 1.12–1.88, P = 0.006) per transfer. Similarly, the clinical pregnancy rate (CPR, 51.5% vs 41.0%, P = 0.003) and implantation rate (35.8% vs 28.6%, P < 0.001) were found associated with the FET cohort, with no significant differences in miscarriage or adverse neonatal outcomes. Multivariate logistic regression found FET to be independently associated with live birth as a protective predictor (adjusted OR 1.48, 95% CI: 1.15–1.92, P = 0.003). Crucially, subgroup analysis found that the superiority of FET was predominantly associated with patients with a sonographically confirmed cesarean scar niche (OR 2.15, 95% CI: 1.45–3.20, P < 0.001), whereas the benefit was marginal in those with an intact scar ( P = 0.125). Conclusion For women with a previous CD, a “freeze‐all” strategy significantly improves LBR and implantation potential compared to fresh ET. This approach is strongly recommended, particularly for patients with a cesarean scar niche, who are the key population benefiting most from FET cesarean.
Xuan et al. (Tue,) studied this question.
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