Mifepristone is an effective oral alternative for the prevention of premature luteinizing hormone surges and/or premature luteinization in women undergoing controlled ovarian hyperstimulation for in vitro fertilization

Abstract

The present clinical study was conducted to investigate the effectiveness of a daily dose of 40 mg mifepristone in preventing premature LH surges in women undergoing controlled ovarian hyperstimulation (COH) for in vitro fertilization and to study the effect of this antiprogestin cotreatment on endometrial receptivity. This was a prospective, open-label, randomized, exploratory study in 15 healthy volunteer oocyte donors who were randomly allocated to the experimental COH group, including mifepristone (group 1), or the control group, using a long protocol with GnRH agonists (group 2), in a ratio of 2:1, i.e. 10 and five subjects, respectively. In group 1, human chorionic gonadotropin (hCG) was randomly administered (group 1A) or was withheld (group 1B) at the end of stimulation, so that two subgroups of five subjects each were formed, differing in the final oocyte maturation trigger. In all patients receiving mifepristone, 50 mg progesterone were administered im at the time of hCG administration to counteract residual antiprogestogenic activity of mifepristone. Serum estradiol, progesterone (P), LH, and FSH levels were monitored in each patient on d 3 and 6 and every 48 h thereafter. Endometrial biopsies were taken 2 and 7 d after hCG or P administration. Endometrial tissue was processed and evaluated in a blinded fashion for endometrial dating and quantitative PCR of at least four genes known to be up-regulated in receptive endometrium. The total FSH dose and duration of treatment in the two arms of the study were similar. The mean LH levels on d 6 of stimulation and the day of hCG/P treatment in the mifepristone group were 0.8 +/- 0.7 and 0.5 +/- 0.6 mIU/ml, and those in control subjects were 2.4 +/- 3.8 and 2.0 +/- 1.7 mIU/ml, respectively. No LH surges were observed in any subject treated with mifepristone. Serum P levels on the day of hCG/P were below the cut-off level (1.2 ng/ml) in all subjects of the mifepristone group (range, <0.5 to 1.05 ng/ml). The mean numbers of cumulus-oocyte complexes retrieved were 11.6 +/- 6.6 and 19.6 +/- 11.8 in the subgroup treated with mifepristone and hCG and in the control group, respectively. The mean percentages of metaphase II, metaphase I, and germinal vesicle stage oocytes were 86.2, 6.9, and 3.4% in the mifepristone group and 68.4, 6.1, and 11.2% in the control group. In the mifepristone group that did not receive hCG and received P only at the end of stimulation, an endogenous LH surge was not observed nor were oocytes obtained. Histological evaluation of endometrial samples in patients treated with mifepristone and hCG (group 1A) confirmed normal development, whereas in patients treated with mifepristone only (group 1B), there was a complete arrest of the endometrial maturation. The expression patterns of glycodelin, IGF-binding protein-7, glutathione peroxidase-3, and solute carrier family 1 member 1 show a striking absence of up-regulation in patients treated with mifepristone (groups 1A and 1B) compared with controls (group 2). The results of this exploratory study provide evidence that mifepristone is effective for the prevention of premature LH surges and/or premature luteinization in women undergoing COH for in vitro fertilization. However, endometrial receptivity status requires additional evaluation after decreasing RU-486 doses before this strategy can be considered as a new alternative to GnRH agonist/antagonist treatment.