Intercycle variability of the ovarian response in patients undergoing repeated stimulation with corifollitropin alfa in a gonadotropin-releasing hormone antagonist protocol

OBJECTIVE: To determine whether individual subject variation in ovarian response between repeated cycles with the same ovarian stimulation protocol can be predicted.

DESIGN: Retrospective data analysis.

SETTING: Multicenter, open-label, uncontrolled clinical trial.

PATIENT(S): Women aged 18-39 from a phase 3, open-label, uncontrolled trial with complete data across all cycles (n = 176).

INTERVENTION(S): Up to three cycles of a single injection of 150 μg corifollitropin alfa for 7 days, then daily recombinant FSH/hMG until three follicles reached ≥17 mm. Gonadotropin-releasing hormone antagonist from stimulation day 5 until day of hCG administration.

MAIN OUTCOME MEASURE(S): Numbers of follicles ≥11 mm on day of hCG in cycles 1-3, transition in ovarian response type between cycles from low (0-<6), normal (6-<18), and high (≥18), and serum FSH concentrations and antral follicle count (AFC) at each cycle start.

RESULT(S): The mean (SD) numbers of follicles ≥11 mm on day of hCG were 13.4 (6.2), 13.3 (5.4), and 13.8 (6.4) in cycles 1, 2 and 3, respectively. Between cycles 1 and 2, 11.9% switched from normal to low or high response, and 12.5% switched from low or high to normal response; 75.6% remained in the same category. Between cycles 2 and 3, 15.9% switched from normal to low or high response, and 10.2% switched from low or high to normal response; 73.9% remained in the same category. These shifts are symmetrical in nature, in that the percentage of subjects who shift from normal to low or high response is comparable to the percentage of subjects who shift from low or high to normal response. Baseline FSH and AFC did not significantly predict transition in ovarian response.

CONCLUSION(S): The variability in ovarian responses between repeated cycles using the same protocol was not explained by baseline FSH and AFC.

CLINICAL TRIAL REGISTRATION NUMBER: NCT00696878 Protocol P05714.