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 0.25 mg 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 P75 versus ⩽P75 and 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.During ovarian stimulation for IVF/intracytoplasmic sperm injection, circulating concentrations of LH should not become too high or too low as the development of mature eggs and the likelihood of ongoing pregnancy may be negatively affected. Gonadotrophin-releasing hormone (GnRH) analogues are applied to prevent premature LH rises but certain regimens may result in relatively low circulating LH concentrations. To examine the relationship between circulating LH concentrations and ongoing pregnancy rates in a GnRH antagonist protocol, data from a large randomized trial, Engage, were retrospectively analysed. In this trial, 1506 patients received corifollitropin alfa or daily recombinant FSH for the first 7 days of stimulation and ganirelix (a GnRH antagonist) from stimulation day 5 onwards. Patients were grouped by their LH concentration (low, normal or high) on stimulation day 8 and the day of human chorionic gonadotrophin (HCG) administration to trigger final egg maturation. The chance of ongoing pregnancy by LH category, with or without adjustment for other factors affecting pregnancy was calculated. There was no significant difference in the chance of pregnancy between patients in the different LH categories, regardless of the day of assessment or the treatment group. In contrast, circulating progesterone (another hormone produced by mature follicles) and the number of eggs retrieved clearly affected the chance of pregnancy. These analyses showed that ongoing pregnancy rates are not influenced by either low or high circulating LH concentrations when using a GnRH antagonist protocol.