Blanca Fuentealba

Effects of a sequential regimen of mifepristone-medroxyprogesterone acetate on ovarian function, endometrial development and hormonal parameters.

The efficacy of a low dose of mifepristone, 5 mg/day for the first 15 days of the menstrual cycle, followed by medroxy-progesterone acetate (MPA), 10 mg/day for the next 13 days, for inhibiting ovulation was assessed in ten volunteers who were treated for three successive cycles. Hormonal determinations in blood and urine samples, ovarian ultrasonography and an endometrial biopsy taken on day 21-24 of the third treatment cycle were used to monitor the cycles. Ovulation was confirmed in 11 of the 30 treated cycles and, in these 11, the LH peak and follicular rupture occurred during MPA treatment periods. Out of 19 anovulatory cycles, 16 had no increase in progesterone levels and another 3 developed a luteinized unruptured follicle. Progestin administration induced secretory changes in the endometrium, but irregular or delayed development was found. Regular withdrawal bleeding occurred in all subjects. These data indicate that the sequential regimen can suppress ovulation while maintaining regular bleeding but increased efficacy is needed for phase II clinical trials.

Role of intrauterine environment in the disappearance of eggs in rats bearing an IUD

Abstract Experiments were done in rats with the purpose of gaining insight into the mechanism by which eggs disappear from the uterine lumen in the presence of an IUD. On day 4 of pregnancy a ligature was placed either between the IUD and the cervix or between the IUD and tubo-uterine junction, so as to divide the uterine lumen in two portions. Autopsy was done on day 5 to determine the number and state of the eggs in the uterus. It was found that eggs disappear when they enter the portion containing the IUD, but they stay intact when they enter into the portion with the IUD excluded by the ligature. The results support the concept that the uterine segment in direct contact with the IUD confers lytic properties upon the intrauterine fluid which diffuse throughout the lumen and cause the disintegration of the eggs.