EFFECT OF 2 ANTIPROGESTINS (MIFEPRISTONE AND ONAPRISTONE) ON ENDOMETRIAL FACTORS OF POTENTIAL IMPORTANCE FOR IMPLANTATION

Objective: To investigate the effects of postovulatory administration of antiprogestins on endometrial factors that may be of importance for successful implantation. Design: Ten women were given 200 mg mifepris tone and an additional 10 women 400 mg of onapristone 48 hours after t he LH surge in urine (LH+2). Main Outcome Measure(s): Biopsies were as sessed for histologic dating and the immunolocalization of[1] leukemia inhibitory factor, [2] 15-hydroxyprostaglandin dehydrogenase, and [3] the cell proliferation marker Ki 67. Hormonal measurements in blood a nd urine were used to monitor the effects on the ovarian cycle. Glycod elin (placental protein 14) concentrations were measured in blood take n on LH+12. Result(s): Treatment with antiprogestins retarded the deve lopment of secretory changes without affecting the length of the lutea l phase. In addition, there was reduced immunostaining for 15-hydroxyp rostaglandin dehydrogenase within glands and a significant reduction i n serum levels of glycodelin. Reduced immunostaining for leukemia inhi bitory factor also was apparent within glands in biopsies taken on LH6 of the treatment cycle. Increased Ki 67 immunostaining was observed on both cycle days after treatment, consistent with P antagonism. Conc lusion(s): Administration of mifepristone and onapristone adversely af fects uterine receptivity. This adds further evidence to support their potential as a method of postovulatory fertility control. (C) 1997 by American Society for Reproductive Medicine.