Pregnancy Outcomes in FET Cycles
During the study, 144 women in the PPOS group and 123 women in the antagonist group complete their first FET. Method of endometrial preparation was different between the two groups. A higher proportion of women used mild stimulation in the PPOS group, while more patients underwent natural cycles in the antagonist group. The number of top quality of embryos after thawing, number of embryos transferred, and endometrial thickness were similar between two groups (Table 2).
Both groups showed comparable ongoing pregnancy, clinical pregnancy, implantation rates, miscarriage, multiple pregnancy and ectopic pregnancy rates. A multivariate logistic regression using the enter method by the women’s age, duration of infertility, stimulation protocol (PPOS / antagonist), insemination method, antral follicle count, basal FSH level, FSH/HMG dosage / duration, serum estradiol levels on the day of hCG, number of oocytes obtained, endometrial thickness, methods of endometrial preparation, number of (top quality) embryos replaced revealed that only the stimulation protocol (OR=2.277, 95% CI: 1.009-5.138) and number of embryos replaced (OR=3.245, 95% CI: 1.259-8.366) predicted the ongoing pregnancy rate of IVF (Table 3). The result of multivariate analysis showed the pregnancy outcome in the antagonist group was favored.