No association between endogenous LH and pregnancy in a GnRH antagonist protocol: part I, corifollitropin alfa.

The relationship between endogenous LH concentrations and ongoing pregnancy rates among normogonadotrophic patients undergoing ovarian stimulation in a gonadotrophin-releasing hormone antagonist protocol were examined. In the Engage trial, 1506 patients received corifollitropin alfa (150 μg) or daily recombinant FSH (rFSH) (200 IU) for the first 7 days of stimulation with 0.25mg ganirelix from stimulation day 5. Patients were retrospectively stratified by serum LH percentiles (< 25th, 25th-75th and >75th) on stimulation day 8 and day of human chorionic gonadotrophin administration. Odds ratios (OR) with and without adjustment for predictive factors for ongoing pregnancy were estimated. LH concentration was not associated with pregnancy rates in either treatment arm, in contrast to ovarian response and serum progesterone. With adjustment for these predictors and age, OR (95% confidence interval) for ongoing pregnancy on stimulation day 8 for LH categories < P25 versus ≥ P25, >P75 versus ≤ P75 and < P25 versus >P75 were 0.75 (0.53-1.06), 1.26 (0.87-1.83) and 0.70 (0.46-1.09) in the corifollitropin alfa arm and 0.80 (0.54-1.17), 1.28 (0.87-1.87) and 0.73 (0.46-1.16) in the rFSH arm respectively. There was also no significant difference in pregnancy rates between LH categories on day of human chorionic gonadotrophin administration with either treatment.