Effect of ovulation before or after intrauterine insemination on pregnancy outcome in patients with unexplained infertility or polycystic ovarian syndrome

Objective To investigate the relationship between ovulation and pregnancy outcomes in patients undergoing intrauterine insemination (IUI). Methods The clinical data from 784 patients, diagnosed with polycystic ovarian syndrome (PCOS) or unexplained infertility, underwent 1624 IUI cycles were analyzed retrospectively. Ovulation was observed by transvaginal ultrasonography on the day of IUI. The clinical pregnancy rate (CPR), abortion rate (AR), and live birth rate (LBR) were analyzed. Results The study included 1031 pre-ovulation IUI cycles (63.49%) and 593 post-ovulation IUI cycles (36.51%). The CPR was 13.05%, the AR was 15.57%, and the LBR was 11.02%. Ovulation before or after IUI affected the CPR (11.06% VS 16.53%, p = .002) and LBR (9.41% VS 13.83%, p = .006) per cycle, but did not affect the AR (14.91% VS 16.33%, p = .149). The sex ratio of children was not related to ovulation (p = .948). After adjusting for baseline characteristics and logistic regression, the CPR (OR = 1.931, 95% CI 1.062-1.931, p = .019) and LBR (OR = 1.389, 95% CI 1.007-1.916, p = .045) of post-ovulation insemination were higher than those of pre-ovulation insemination significantly. Conclusion Pregnancy outcomes were affected by ovulation on the day of IUI in patients with unexplained infertility or PCOS. Post-ovulation insemination may improve the CPR of IUI.