Reproductive outcomes following assisted reproductive technology after previous caesarean section: data from the Swiss National Registry.

Introduction: Caesarean section rates have risen worldwide, exceeding the rate of 10%-15% recommended by the WHO. This increase is driven by factors such as advanced maternal age, broader indications for caesarean section (CS), and increased use of assisted reproductive treatment (ART). Previous research, including meta-analyses, suggests that prior CS delivery (CSD) negatively affects the reproductive outcomes in ART, such as lower live birth rates (LBR) and potential subfertility, although the quality of the evidence is variable. Obstetric complications associated with CSD, for instance, uterine rupture and placental abnormalities, highlight the need for further investigation. This study therefore evaluates the impact of CSD on ART outcomes using a comprehensive national registry. Materials and methods: This study includes a cohort of 3,266 women who underwent caesarean section delivery ( Results: The characteristics of the patients in both study groups were similar. Following the first embryo transfer, the clinical pregnancy rates were lower after CSD in univariate analysis (38.7% vs. 43.4%; Conclusions: A history of caesarean section was associated with lower clinical pregnancy rates across successive embryo transfers following ART. No significant association was observed after the first embryo transfer following multivariable adjustment, and miscarriage rates were not affected by the mode of the previous delivery. Further prospective studies, including imaging assessment of caesarean scar defects and isthmocele, are required to determine whether the observed association is related to caesarean section itself or to secondary scar pathology.