Does the elevated estradiol level on the day of human chorionic gonadotropin administration affect embryo quality among women undergoing in vitro fertilization

OBJECTIVE To evaluate the association between estradiol (E2 ) levels on the day of human chorionic gonadotropin (hCG) administration and embryo quality during in vitro fertilization (IVF) cycles. METHODS A retrospective study of 6676 IVF cycles among women treated at the Reproductive Center of The First Affiliated Hospital of USTC, Hefei, China, from June 2014 to May 2017. E2 levels on hCG day were divided into four groups by 25th percentile: 0-1763 pg/mL (group I), 1763-3692 pg/mL (group II), 3692-4800 pg/mL (group III), and higher than 4800 pg/mL (group IV). Analysis of variance and multiple linear regression were used to test associations. RESULTS There were significant differences in the frequency of high-quality embryos between group I (51.6% ± 1.1%) and groups II (65.6% ± 0.8%), III (62.1% ± 0.7%), and IV (62.3% ± 0.7%). Using E2 as a dummy variable and group II as a control, multiple linear regression showed that E2 levels were associated with the frequency of high-quality embryos obtained (P<0.05). CONCLUSION Serum E2 on hCG day had an impact on embryo quality. Higher E2 levels did not produce the most high-quality embryos; the highest frequencies were achieved for E2 levels within 1763-3692 pg/mL.