Comparison of two cancellation strategies to lower the risk of multiple pregnancies in gonadotropin stimulated intrauterine insemination cycles

Objective: To compare two cancellation policies in controlled ovarian stimulation-intrauterine insemination (COS-IUI) cycles to lower the risk of multiple pregnancies (MP). Design: We performed a bicentric retrospective cohort study in two academic medical centers: Angers (group A) and Besancon (group B) University Hospitals. We included 7056 COS-IUI cycles between 2011 and 2019. In group A, cancellation strategy was based on an algorithm taking into account the woman's age, the serum estradiol level, and the number of follicles of 14 mm or greater on ovulation trigger day. In group B, cancellation strategy was case-by-case and physician-dependent, based on the woman's age, number of follicles of 15 mm or greater, and the previous number of failed COS-IUI cycles, without any predefined cut-off. Our main outcome measures were the MP rate (MPR) and the live-birth rate (LBR). Results: We included 884 clinical pregnancies (790 singletons, 86 twins, and 8 triplets) obtained from 6582 COS-IUI cycles. MPR was significantly lower in group A compared with group B (8.1% vs 13.3%, P = 0.01), but LBR were comparable (10.8% vs 11.8%, P = 0.19). Multivariate logistic regression found the following to be risk factors for MP: the "cancellation strategy" effect (adjusted odds ratio [aOR] 1.63, 95% confidence interval [CI] 1.02-2.60) and the number of follicles of 14 mm or greater (aOR 1.39, 95% CI 1.16-1.66). Cycle cancellation rate for excessive response was significantly lower in group A compared with group B (1.3% vs 2.4%, P < 0.001). Conclusions: The use of an algorithm based on the woman's age, serum estradiol level and number of follicles of at least 14 mm on trigger day allows the MPR to be reduced without impacting the LBR.