A lesson from IVF endocrinology: the importance of the follicular phase to success and failure in non-IVF cycles.

Sixty-three patients treated with exogenous gonadotropins for a total of 232 non-IVF cycles were monitored by serum E2 and/or total urinary estrogen excretion. The endocrine profile of follicular phase during HMG-HCG stimulation was evaluated with regard to an effect on the pregnancy rate. Six different follicular phase patterns were observed: A-profiles (daily exponential increase of sE2 or total urinary estrogen values followed by a sustained exponential increase on the day after HCG injection) seem to be necessary to obtain pregnancy, being followed by conception in 21.5% of all cases. Other profiles have lower conception rate (10%); no conception occurred when non exponential E2 rise was observed. The different responses are not related to total dosage of HLG administered. Patients who were treated for hypogonadotropic hypogonadism had a high pregnancy rate (80%) even in absence of post-HCG estrogen rise (G-endocrine profiles. Women aged 35 years must have significantly higher doses of gonadotropins to obtain A-profiles. Monitoring by E2 seems to be more adequate than the TUE only (conceptual pregnancy rate/cycle of 15.25%, versus 10.34%). In conception cycle, midluteal E2/P ratio never exceeds 50.