Data Analyses
Clinical pregnancies were confirmed by the presence of a fetal heartbeat on ultrasound scanning 7 weeks after insemination. Miscarriage was defined as loss of a clinical pregnancy before the 28th week of gestation. Live birth was defined as delivery of a live neonate after 28 weeks’ gestation. Our primary outcome measure was live birth rate. Our secondary outcomes included clinical pregnancy rate and miscarriage rate. In light of the significant differences detected related to intrauterine insemination number between the hCG group and the urinary LH groups , a subgroup analysis was performed to assess the impacts of one vs. two inseminations in a given cycle for both the hCG and urinary LH groups.
Statistical analysis was performed using SPSS Statistics 20.0 (IBM). Mean values and standard deviations were calculated for each continuous variable, whereas percentages were determined for the categorical variables. Continuous variables were compared with Student’st -tests. Categorical variables were compared with chi-squared and Fisher’s exact tests. A single, multivariate logistic regression analysis (incorporating ovulation timing method as a categorical explanatory variable) was performed to assess the independent effect of hCG administration on reproductive outcomes after adjustment for possible confounding factors, including maternal age, BMI, number of intrauterine insemination events, and basal hormone levels (FSH, LH, estradiol, AMH). A P value <0.05 was considered statistically significant.