| Abstract: | Cylindrical rings, made of silicone rubber impregnated with medroxyprogesterone acetate were placed in the vaginas of 3 regularly menstruating women on the first cycle day. Silastic rings without medication were used in 3 controls. During the 28 days that the rings were in place, there was continuous systemic absorption of the progestogen as evidenced by elevation of the basal body temperature, shift in maturation index, abolition of the midcycle LH peak, and change in the endometrial histology. In the 3 controls, no significant alterations occurred in any of the parameters measured (BBT, vaginal cytology, endometrial biopsies and gonadotrophins) as compared with the cycles before and after insertion of the ring. After removal of the rings in the test group, the advent of withdrawal bleeding and a fall in the basal body temperature indicated a prompt termination of drug activity. Presumptive evidence of ovulation followed shortly thereafter. It is hoped that this method of administering a progestogen may be developed for family planning. |
