The Ovarian Response After Follicular Versus Luteal Phase Stimulation with a Double Stimulation Strategy

The double-ovarian stimulation strategy has been proposed to optimize the number of oocytes retrieved within the shortest possible timeframe. The objective of this study is to explore the effectiveness of luteal phase (LP) ovarian stimulation as compared to the previous follicular phase (FP) stimulation in a double stimulation strategy. We conducted an observational cohort study of women scheduled for a double stimulation protocol between March 2014 and June 2017, who had completed the FP controlled ovarian stimulation (COS 1) and started the LP stimulation (COS 2) in the same cycle. Women received equivalent daily doses of gonadotropins in combination with GnRH-antagonist protocol for both the COS 1 and the COS 2 performed during the same cycle. Ovulation was triggered using GnRH-agonist in the two stimulations. The primary outcome was the number of oocytes retrieved. A total of 77 patients were included in the analysis. The number of oocytes retrieved after COS 1 was significantly higher than after the COS 2 (5.25 ± 3.38 for COS 1 versus 3.83 ± 3.14 for COS 2; p = 0.001). The duration of the stimulation was significantly shorter, the total dose of injected gonadotropins was significantly lower, and the estradiol level on the trigger day was significantly higher with COS 1 as compared to COS 2. Stimulation during the LP in a double-successive stimulation strategy results in a lower ovarian response as compared to the FP equivalent daily dose stimulation.