Results
Table 1 shows the baseline characteristics. We identified 41,546 cycles who met the study criteria, including 1590 women with elementary school graduate or less, 10996 women with middle graduate, 8354 with high school graduate, and 20606 with college graduate or higher. The distribution of baseline characteristics of the study population is presented in Table 1. There was a significant difference in baseline characteristics between groups, with elementary school or less education level women more likely to be older, have longer infertility duration, higher BMI, more secondary infertility, IVF insemination, fresh embryo transfer, and double embryo transfer, while less no. of oocyte retrieved and agonist protocol in the fresh cycle. The live birth rate, miscarriage rate, and clinical pregnancy rate in elementary school graduate or less were lower compared to other groups.
Univariate analysis was performed to evaluate each variable’s effect on the live birth rate (Table 2). Female age, infertility duration, BMI, secondary infertility, antagonist, and other protocol in the fresh cycle and frozen embryo transfer were negatively associated with live birth, while endometrial thickness, no. of oocyte retrieved, and double embryo transfer were positively associated with live birth. Interaction and stratified analyses were shown in Table S1. There were no significant interactions in any of the subgroups (p>0.05 for all comparisons).
Compared with women with an education corresponding to elementary school graduate or less, there was an increased rate of live birth among women with higher educational levels in the crude model. However, after adjusting for female age, infertility duration, BMI, EM thickness, no. of oocyte retrieved, infertility type, protocol in the fresh cycle, fertilization type, time of transfer, and no. of embryo transferred, women’s educational level was not associated with live birth.