Clinical and perinatal outcomes of fresh single-blastocyst-transfer cycles under an early follicular phase prolonged protocol according to day of trigger estradiol levels.

We concluded that serum E2 levels on the day of trigger were not good predictors of live birth rate or perinatal and obstetrical outcomes. However, we found that high E2 levels may not be conducive to persistent pregnancies. The E2 level on the day of trigger can still be used to predict the incidence of early onset severe OHSS in the fresh SBT cycle.