• K E Greene, L M Kettel, and S S Yen.
• University of California-San Diego, School of Medicine, La Jolla.
• Fertil. Steril. 1992 Aug 1; 58 (2): 338-43.

ObjectiveTo examine hormonal and endometrial responses to intermittent low-dose RU486 administration in the luteal phase of the menstrual cycle.DesignProspective open trial in which subjects serve as their own controls.Patients/ParticipantsEight normal cycling women.InterventionsRU486 (10 mg, orally) was administered 5 and 8 days after urinary luteinizing hormone (LH) surge of treatment cycle.Main Outcome MeasuresDaily serum concentrations of LH, follicle-stimulating hormone, estradiol (E2), and progesterone (P) were determined in control, treatment, and recovery cycles (n = 5) or treatment and recovery cycles (n = 3). Changes in endometrial morphology and immunohistochemical staining for P receptor (PR) and E2 receptor (ER) were determined during control (or recovery) and treatment cycles.ResultsCycle length and hormonal patterns were unaltered after treatment with RU486. As demonstrated by reduced stromal edema and delayed glandular development, endometrial dyssynchrony occurred in all eight treatment cycles. In addition, seven of eight treatment cycle endometria demonstrated a decrease in PR staining without consistent change in ER staining.ConclusionsTwo low doses of RU486 given 72 hours apart during the luteal phase of the cycle disrupted ongoing endometrial maturation without altering the hormonal and time course of the menstrual cycle. This study provides a basis for the development of a novel form of luteal contraception.

67 keywords...

hide…