Results
A total of 5610 patients who were treated with IUI from January 2012 until December 2017 were included in the study. Despite the fact that some women received several IUI treatments per fertility cycle, only data for the first treatment (either single or double insemination) of each woman was included in the analysis.
The baseline characteristics and hormonal profiles of the patients in the hCG and spontaneous ovulation group are presented in Table 1. No significant differences were observed regarding BMI, basal AMH, or estradiol concentration between patients of the two groups, while slight differences were detected in age and basal FSH and basal LH concentrations.
Pregnancy outcomes are shown in Table 2. In crude analysis, compared to the spontaneous ovulation group, the hCG group had significantly higher rates of clinical pregnancy (27.40% versus 22.73%, OR (95% CI): 1.28 (1.11–1.49); P =0.001) and live birth rates (24.52% versus 20.13%, OR (95% CI); 1.29 (1.11-1.50); P =0.001). Additionally, no difference in the rate of miscarriage was observed between the two groups (10.50% versus 11.46%, OR (95% CI): 0.91(0.60-1.36);P =0.671). Note that the significantly increased clinical pregnancy and live birth rates of the hCG group were still detected after adjustment for a number of confounding factors (Table 2).
To assess the effect of intrauterine insemination number on pregnancy outcomes, a subgroup analysis (single IUI, double IUI) was performed (Table 3, 4). Among women who received double IUI, there was no difference between the hCG group and spontaneous ovulation group in the rates of clinical pregnancy (27.30% VS 25.00%, OR (95% CI): 1.12 (0.88–1.44); P =0.343) or live birth (24.46%VS20.66%, OR (95% CI): 1.24 (0.96–1.62); P =0.102). However, among single IUI patients, the hCG group women achieved significantly higher rates of clinical pregnancy (28.23% versus 21.80%, OR (95% CI): 1.41 (1.09–1.81); P =0.009) and live birth (25.00% versus 19.91%, OR (95% CI): 1.34 (1.03–1.74); P =0.032).