The impact of serum estradiol level prior to progesterone administration on live birth rate in single frozen-thawed blastocyst transfer cycles

Abstract Research Question To investigate whether serum estradiol (E2) levels on the day of progesterone initiation predict live birth rate in single, autologous frozen-thawed blastocyst transfers (FBTs) following artificial endometrial preparation (EP). Design This retrospective study included the first transfers of 468 patients with unexplained or tubal factor infertility who underwent freeze-all cycles using single, top-quality blastocyst after artificial EP from January 2015 to January 2018. The patients were stratified into four groups based on the percentiles of serum E2 levels on the day of progesterone initiation; group 1 ( 75th percentile). The primary outcome was live birth rate. The secondary outcomes were implantation, clinical pregnancy and multiple pregnancy rates. Receiver operating characteristic (ROC) curves were generated to exhibit the role of serum E2 levels in predicting the successes of implantation, clinical pregnancy and live birth. Results The live birth rate was 51.6%, 55.1%, 54.9% and 56.4% for group 1, group 2, group 3 and group 4, respectively (p>0.05). The groups also showed similar implantation and clinical pregnancy rates. The ROC analysis revealed that serum E2 levels on the day of progesterone initiation was not predictive for implantation (AUC: 0.490, p=0.98) clinical pregnancy (AUC: 0.507, p=0.80) and live birth (AUC: 0.514, p=0.60). Conclusions Serum E2 level monitoring just prior to progesterone administration does not appear to be predictive for live birth rates in good prognosis patients undergoing single, autologous FBTs after artificial EP. Therefore, the current practice of monitoring serum E2 level is not supported by our study.