Other Potential Obstetrical and Gynecological Applications

A sequential regimen using mifepristone (10 mg) and the progestin nomegestrol acetate (5 mg) was studied in 30 women for 12 consecutive cycles without pill-free days. Mifepristone was administered for 15 days and this was immediately followed by the progestin for 13 days. One pregnancy occurred in 359 woman-months of exposure. This study has been published in abstract form [81, 82], 

Other strategies are based on the observation that mifepristone can retard endometrial development. In two studies, a total of 53 women received 200 mg mifepristone 48 h after the luteinizing hormone (LH) surge and there were only three pregnancies in a total of 335 cycles [83, 84]. In view of its complexity, a method dependent on the precise timing of the LH surge does not represent a practical approach to contraception. 

Weekly administration of mifepristone in doses as high as 25 mg do not consistently inhibit ovulation [85], However, this regimen does interfere with normal endometrial development. No pregnancies occurred when once weekly administration of mifepristone (25 and 50 mg) was given for 6 months to a total of 76 women. There were a total of 456 women-months of use [86]. 

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