To compare the clinical outcomes of intrauterine insemination (IUI) with or without ovulation induction (OI), IUI cycles from January 2008 to December 2017 in Zhoushan Maternity and Child Healthcare Hospital were included, consisting of 455 natural cycles and 536 OI cycles. The overall clinical pregnancy rate did not differ between the two groups (P > 0.05). Stratified by OI medications such as clomiphene (CC), human menopausal gonadotropin (HMG) and follicle stimulating hormone (FSH), the pregnancy rates in HMG, CC, CC+HMG, and FSH/FSH+HMG groups were 11.70%, 13.58%, 15.95%, and 13.46%, respectively, but the difference was not significant compared with natural cycles (P > 0.05). Stratified by infertility etiology, the pregnancy rate was significantly higher in stimulated cycles than natural cycles with ovulation disorders (P < 0.01) and unexplained factors (P < 0.01) while it was significantly lower regarding cervical factors (P < 0.01), endometriosis (P < 0.05), male factor (P < 0.01) and other female factors. There was no strong difference of pregnancy rate for biparental causes (P > 0.05). Stratified by age category, women over 35 had higher pregnancy rate in stimulated cycles compared with natural cycles (18.75 vs. 12.24%; P < 0.05), while women under 35 had no significant difference of pregnancy rate between the two groups (13.65 vs 13.05%; P > 0.05). However, there was no significant difference between each ovarian stimulation group and natural cycle group regardless of the infertility causes or age categories. To conclude, IUI-OI could achieve a higher overall pregnancy rate for women over 35 and infertile patients with ovulation disorders and unexplained factors.
Keywords: Intrauterine insemination (IUI); clinical pregnancy rate; natural cycles; ovulation induction (OI); stimulated cycles.