Stimulation day-six serum estradiol: a predictive indicator for the probability of embryo cryopreservation in...

To evaluate the predictive value of stimulation day six serum estradiol (E2) for the probability of embryo cryopreservation after fresh embryo transfer in intracytoplasmic sperm injection (ICSI) cycles.

The study included 282 ICSI cycles for different causes of infertility, provided that the age of the female partner was <40 years and her basal follicle stimulating hormone <10 IU/L.

Alexandria IVF/ICSI center.

Primary outcome measures are stimulation day-six serum E2, and rate of embryo cryopreservation, after transfer of three good-quality embryos. Secondary outcome measures are pregnancy rate per fresh embryo transfer, and other intermediate variables of the ICSI cycle.

Patients were stratified into three groups according to day-six serum E2 levels: Group I with values <400 pg/mL; Group II, between 400 and 900; and Group III with values >900. The mean number of oocytes retrieved was 6.3, 8.9, and 12.4; the mean number of obtained embryos was 3.3, 4.8, and 6.7; and pregnancy rates were 18.1, 36.2, and 44.7% in the three groups, respectively. Rate of embryo cryopreservation, after transfer of three good-quality embryos was 70.7% in Group III, and 26.5% in Group I. (P = 0.01). The negative predictive value of day-six E2 <400 pg/mL for freezing was 83% while day-six serum E2 >900 pg/mL has a sensitivity of 55%, specificity of 72% and positive predictive value of 50% for embryo freezing.

Higher stimulation day-six estradiol was associated with a higher probability of cryopreservation, and a higher pregnancy rate.