Correlation between estradiol levels on day of HCG trigger and the number of mature follicles, number of oocytes retrieved, and the number of mature oocytes (M2) after oocyte aspiration in ICSI cycles

Background Estradiol is an important marker of ovarian response to ovarian stimulation in ART cycles. The study tries to find the correlation of serum estradiol on the day of HCG trigger to the number of follicles, the number of oocytes retrieved, and the number of mature oocytes, and also, to correlate estradiol per follicle and estradiol per oocyte on the day of HCG, to the number of oocytes retrieved, and to the number of mature oocytes. It is a cross sectional study using retrospective data. Results The data of 232 patients were analyzed. Our study showed a positive correlation between estradiol levels and the number of follicles (NF) ( r = 0.592, p < 0.001), number of retrieved oocytes (NRO) ( r = 0.576, p < 0.001), and number of mature oocytes (NMO) ( r = 0.554, p < 0.001). E/follicle ratio did not have a significant correlation with NRO and NMO. E/Oocyte ratio had a strong negative correlation with NMO ( r = −0.280, p < 0.001) Conclusions Serum estradiol had a positive correlation with NF, NRO, and NMO. But E/O had a strong negative correlation with NMO. These results indicate that estradiol levels can be used as an important clinical tool in the prediction of oocyte and mature oocyte yield in ART cycles. Reproductive outcome in ART cycles is largely dependent on the number of oocytes and mature oocyte yield. Estradiol levels on the day of HCG appear to strongly correlate with the outcome of ART cycles.