Value of the serum estradiol level on the day of human chorionic gonadotropin injection and on the day after in predicting the outcome in natural in vitro fertilization intracytoplasmic sperm injection cycles

Objective: To predict the risk of premature ovulation and possibility of pr egnancy in natural IVF/ICSI cycles on the basis of the estradiol (E-2) leve l on the day of hCG injection and on the day after. Design: A prospective study. Setting: Hospital research program. Patient(s): One hundred sixty-four women undergoing 305 IVF/ICSI natural cy cles. Intervention(s): Serum E-2 levels were measured similar to 12 h before (day 0) and 12-17 h after hCG administration (day 1). Main Outcome Measure(s): E-2 levels on day 0 and day 1, the ratio of the da y 1 to day 0 levels, and cycle outcome. Result(s): In cycles with premature ovulation and in conception cycles, the average E-2 level on day 0 was statistically significantly higher than in other cycles, whereas the E-2 ratio was statistically significantly lower. Multiple logistic regression was used to determine the connection of the E- 2 level on day 0 (B0 = -0.742, B = 2.147, P =.01) and the E-2 ratio (B0 = - 0.742, B = -3.135, P<.001) with premature ovulation. Only the E-2 ratio (B0 = 0.659, B = -2.209, P =.0068) was significantly connected with conception . Conclusion(s): In predicting the outcome of natural IVF/ICSI cycles, the im portance lies not in the E-2 level on the day of hCG administration or on t he day after, but rather in the E-2 ratio. (C) 2001 by American Society for Reproductive Medicine.