Does the estradiol level on the day of human chorionic gonadotropin administration predict the clinical outcome of controlled ovarian hyperstimulation?

OBJECTIVE: To investigate the effect of serum estradiol (E2) levels on the day of human chorionic gonadotropin (hCG) administration on the outcome of controlled ovarian hyperstimulation (COH) in both long gonadotropin-releasing hormone (GnRH) agonist and GnRH antagonist protocols. MATERIALS AND METHODS: This study included 212 in vitro fertilization-embryo transfer (IVF-ET) cycles performed with either long GnRH agonist or GnRH antagonist protocols were classified into three groups according to serum E2 levels measured on the day of hCG injection: < 2,000 pg/ml, 2,000-4,000 pg/ml, and > 4,000 pg/ml. The three groups were compared according to age, number of retrieved oocytes, number of transferred embryos, and pregnancy rates for each of the stimulation protocols. RESULTS: The long and antagonist protocols were performed in 130 and 82 cycles, respectively. The pregnancy rates were 21.5% (28/130) and 23.2% (19/82) in the long- and antagonist-protocol groups, respectively. Serum E2 levels were measured on the day of hCG administration as < 2,000 pg/ml in 65 cycles, 2,000-4,000 pg/ml in 76 cycles, and > 4,000 pg/ml in 71 cycles. The number of retrieved oocytes increased in parallel to serum E2 levels (p = 0.001). However, there was no significant difference among groups in the pregnancy rates (p = 0.116). Similarly, the number of retrieved oocytes increased in parallel to serum E2 levels in both of the protocol groups (p value was 0.001 in both long GnRH agonist and antagonist protocols), but there was no correlation between the pregnancy rates and serum E2 levels (p value of long GnRH agonist protocol was 0.254 and thep value of antagonist group was 0.349). CONCLUSION: The serum E2 level on the day of hCG administration does not predict the pregnancy outcome in IVF with either long GnRH agonist or GnRH antagonist protocols.