The effect of the day of initiation of ovarian stimulation in the day of luteinizing hormone surge and outcome of in vitro fertilization.

It was hypothesized that the day of initiation of ovarian stimulation may influence the day of the luteinizing hormone (LH) surge onset and follicular development. Two groups of 52 patients were randomly selected to commence ovarian stimulation on either day 2 or day 4. The mean +/- standard deviation day of the LH surge was 11.0 +/- 0.9 for day 2 and 12.2 +/- 0.9 for day 4 (P less than 0.001), and the day of human chorionic gonadotropin (hCG) administration was 10.7 +/- 1.2 for day 2 and 11.4 +/- 0.9 for day 4 (P less than 0.02). The two groups also differed significantly in the mean number of days of human menopausal gonadotropin (hMG) administration (day 2, 7.4 +/- 2.7, versus day 4, 6.3 +/- 2.5), and the mean number of vials of hMG administered (day 2, 10.4 +/- 3.2, versus day 4, 8.1 +/- 2.9). However, the mean estradiol level on the day of the LH surge or hCG administration, the number of oocytes collected and fertilized, the number of embryos transferred, and the pregnancy rates were not significantly different. In conclusion, the day of the LH surge or hCG administration can be influenced by the day of initiation of ovarian stimulation, and the initiation of ovarian stimulation around day 4 of the menstrual cycle is clinically more efficient than initiation of follicular development early in the follicular phase.