[Value of serum estradiol and progesterone levels on hCG trigger day on clinical outcomes after fresh embryo transfer with GnRH antagonist regimen].

Objective: To evaluate estrogen and progesterone levels' impact and combined effects on clinical pregnancy rate and live birth rate in gonadotropin-releasing hormone antagonist regimen with fresh embryo transfer on human chorionic gonadotropin (hCG) trigger day. Methods: The data of patients who underwent in vitro fertilization or intracytoplasmic sperm injection at The First Affiliated Hospital of Nanjing Medical University from January 2011 to January 2021 were collected. According to the number of retrieved oocytes, they were divided into the normal response group (5-15 oocytes) and the low response group (<5 oocytes). The ovulation induction outcomes and pregnancy outcomes of the two groups were compared. Statistical analysis was conducted using t test or chi-square test, and confounding factors were adjusted through multivariate regression models, and the hormone cut-off values were determined. Results: Among 3 595 patients, compared with the normal response group (n=2 614), the age of women in the low response group (n=981) had a negative impact on pregnancy outcomes (P<0.001), while the number of antral follicles, anti-Müllerian hormone, endometrial thickness and embryo quality were positively correlated with pregnancy outcomes (all P<0.05). Multivariate regression analysis indicated that in the normal response group, a higher level of estradiol on hCG trigger day were significantly associated with decreases in clinical pregnancy rate (OR=0.965, 95%CI: 0.946-0.984; P<0.001) and live birth rate (OR=0.973, 95%CI: 0.954-0.993; P=0.008). In the low response group, higher progesterone level was associated with poorer pregnancy outcomes (clinical pregnancy rate: OR=0.875, 95%CI: 0.794-0.961, P=0.006; live birth rate: OR=0.876, 95%CI: 0.793-0.966, P=0.009). The hormone cut-off values: the estradiol cut-off values for the normal and low response groups were 14 000 pmol/L and 6 000 pmol/L respectively, and the progesterone cut-off values for the normal and low response groups were 5.8 nmol/L and 4.0 nmol/L. When hormone levels exceed the cut-off values, pregnancy outcomes significantly decline, and the negative impact on pregnancy outcomes was most significant when both hormones increase (clinical pregnancy rate: normal response group P=0.010，low response group P=0.020; live birth rate: normal response group P=0.028，low response group P=0.014). Conclusions: In patients with normal response, compared with progesterone on hCG trigger day, the increase in estradiol significantly reduces the clinical pregnancy rate and live birth rate of fresh embryo transfer, which should be paid attention to. In patients with poor response, both higher progesterone and estradiol levels on hCG trigger day could significantly reduce the clinical pregnancy rate and live birth rate of fresh embryo transfer, and the combined effect is more obvious. It is recommended that for patients whose progesterone and estradiol on the hCG day exceed the corresponding cut-off values, all embryos should be frozen and embryo transfer should be postponed.