Follicular phase hormonal profiles during administration of leuprolide for in vitro fertilization.

Hormonal changes induced during short-term administration of leuprolide were evaluated during the follicular phase in 57 patients who completed an IVF cycle. They were compared with those of 14 patients who were placed on long-term suppression. There was an unexpected abnormal increase in serum progesterone during the first week of the cycle in nine of the 57, with no significant change in the fertilization and cleavage rate; however, no pregnancy was achieved in this group. Transient mild elevation of progesterone was also detected in 16 patients with no adverse effect on fertilization and the outcome of the IVF. In the long protocol, the tonic levels of LH, FSH, and progesterone remained low throughout the follicular phase. The total number of pregnancies was higher in the short suppression regimen, but the full-term pregnancy rates were similar in both protocols.