Effects of letrozole combined with human menopausal gonadotrophin in ovarian stimulation for intrauterine insemination cycles.

BackgroundThe effects of letrozole plus human menopausal gonadotropin (HMG) on ovarian stimulation (OS) of intrauterine insemination (IUI) cycles were examined.MethodsIn all, 1,005 IUI cycles were included in this study. Couples underwent natural cycle (NC) IUI (n=150) or IUI after OS with letrozole (n=207) or IUI after OS with letrozole + HMG (n=648).ResultsThe clinical pregnancy rates were 9.0%, 13.0%, and 17.0%, and the live birth rates were 7.0%, 9.0%, and 14.0% in the NC, letrozole, and letrozole + HMG IUI groups, respectively. The twin pregnancy rate of the letrozole + HMG group (11.0%) was higher than that of the NC (7.0%) and letrozole groups (4.0%). To date, the only triplet pregnancies to occur were in the letrozole + HMG group. On the day of human chorionic gonadotropin (hCG), the number of follicles with an average follicle diameter greater than 18 mm in the letrozole + HMG group (1.21±0.56) and letrozole group (1.14±0.48) was greater than that in the NC group (0.85±0.36). The thickness of the endometrium in the letrozole + HMG group (8.8±2.1 mm) was significantly greater than that in the letrozole group (7.3±1.6 mm).ConclusionsThe letrozole + HMG protocol of OS in IUI can improve follicular development, increase the thickness of endometrium, significantly increase the live birth rate, but not significantly increase the multiple pregnancy rate.