Association of the Number of Embryos Transferred with Ectopic Pregnancy after Embryo Transfer in Patients with Salpingectomy or Proximal Tubal Occlusion

Background: With the prevalence of assisted reproductive technology (ART), the incidence of ectopic pregnancy (EP) is increasing, especially in patients with salpingectomy or proximal tubal occlusion. Methods: A total of 11,609 women who were undergoing ART and had undergone salpingectomy or proximal tubal occlusion, and 5388 women who achieved a clinical pregnancy were included in the study. Statistical analysis was used to determine whether the number of embryos transferred was associated with EP. Results: Both the number of embryos transferred and the day of embryo transfer differed significantly between those with and without EP (p < 0.05), while the number of embryos transferred was associated with interstitial pregnancy (IP) (p < 0.05) in those undergoing frozen-thawed embryo transfer (ET) cycles. Following multivariate modeling, the odds of having an EP in women undergoing frozen-thawed ET cycles increased with the number of embryos transferred (odds ratio [OR] 2.003, 95% confidence interval [95% CI] 1.036-3.876). Conclusions: The embryo transfer number was considered a risk factor for EP in patients undergoing frozen-thawed ET who had undergone salpingectomy or proximal tubal occlusion.