Comparison of different regimens of a gonadotropin-releasing hormone analog during ovarian stimulation for in vitro fertilization *

Three treatment protocols were used in 156 in vitro fertilization cycles. Leuprolide acetate was begun on day 1 of the cycle in one group (n=20), on day 3 in another (n=48), and the third control group (n=88) did not receive the gonadotropin-releasing hormone analog. Human menopausal gonadotropin was initiated on day 3 in all groups. Peak estradiol (E 2 ) levels and the mean numbers of mature oocytes and embryos transferred per cycle were significantly greater in the day 3 group than in either the day 1 or control groups. Patients who received the day 3 protocol had significantly fewer cancelled cycles. A decline in E 2 was observed on the third day of analog administration in certain patients, particularly those on the day 1 protocol. Follicle-stimulating hormone and luteinizing hormone (LH) levels increased two- to fivefold 24hours after initiation of the analog. Thereafter the gonadotropin levels fell, but nevertheless remained above those of controls for most of the cycle. Hence, it appears that enhanced follicular growth attributed to the early transient rises in gonadotropins can be coupled to a suppression of endogenous LH surges in leuprolide-treated women. These beneficial effects seem to be more likely to occur if leuprolide is initiated on cycle day 3 rather than day 1.