High estradiol levels in fresh embryo transfer cycles are not associated with detrimental impact on birth outcomes

There is an unclear relationship between estradiol levels and fresh embryo transfer (ET) outcomes. We determined the relationship between estradiol on the day of trigger, in fresh ET cycles without premature progesterone elevation, and good birth outcomes (GBO). We identified autologous fresh ET cycles from 2015 to 2021 at multiple clinics in the USA. Patients with recurrent pregnancy loss, uterine factor, and elevated progesterone on the day of trigger (progesterone > 2 ng/mL or 3-day area under the curve > 4.5 ng/mL) were excluded. The primary outcome was GBO (singleton, term, live birth with appropriate weight). Log-binomial generalized estimating equations determined the likelihood of outcomes. Of 17,608 fresh ET cycles, 5025 (29 ≥ 4000 pg/mL had a greater likelihood of GBO compared to cycles < 1000 pg/mL (aRR = 1.32, 95 ≥ 4000 pg/mL, aRR 0.96, 95