Suppression of ovarian function with the transdermally given synthetic progestin ST 1435

Abstract

To study transdermal administration of the synthetic progestin ST 1435 and effectiveness of the steroid in suppression of ovarian function. The effect of transdermal administration of the synthetic progestin ST 1435 in suppression of ovarian function was studied in a short term (17 to 93 days) study in healthy regularly menstruating women. The outpatient clinic of the City Maternity Hospital, Helsinki, Finland. Nine women used the progestin ST 1435 transdermally during a total of 21 menstrual cycles. Treatment was started on the 5th day of the menstrual cycle and continued for 17 to 93 days. Three different daily doses (0.5, 0.8, and 1.0 mg) were tested. The steroid was applied to the periumbical area once a day in a gel. Serum concentrations of ST 1435, progesterone, and estradiol (E2) were determined during the luteal phase of control cycles and in a total of 16 treatment cycles. Bleeding records were kept and side effects registered. Transdermal absorption of the progestin ST 1435 resulted in relatively constant serum concentrations in each subject, depending on the dose used. All doses caused changes in ovarian function. With the 0.5-mg/d dose, inhibition of ovulation was observed in three of five treatment periods. The 0.8-mg/d dose was high enough to inhibit ovulation in 7 of 10 cycles analyzed. With the 1.0-mg/d dose, the serum concentrations of the progestin were high, and anovulation was seen. Serum E2 concentrations were variable in all cases; occasional high peak values were seen, typical of progestin treatment. Bleeding control was variable; irregular bleeding was seen, especially in anovulatory cases. A 0.8-mg dose of the progestin ST 1435 administered transdermally once a day appeared to suppress ovulation, if properly applied, and excessive suppression of ovarian function was not seen. The steroid was well accepted. The synthetic progestin ST 1435 given transdermally represents an effective alternative for inhibition of ovulation and for progestin therapy.