Intravaginal administration of conjugated estrogens in premenopausal and postmenopausal women

Daily doses of 0.625 mg of conjugated estrogens were administered intravaginally for 14 days to 12 postmenopausal women (six with highly atrophic and six with slightly atrophic vaginal mucosa), resulting in vaginal mucosae similar to those found in premenopausal women in all 12 subjects. In a second experiment, serum estrogens, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were determined before and hourly for six hours after a single intravaginal dose of 0.625 mg of conjugated estrogens was given to five postmenopausal women and to five premenopausal women on cycle days 6-8. Serum levels of unconjugated immunoreactive estrogens and total estrone increased rapidly in four of five postmenopausal women. Luteal phase values were found after only two hours, but there were no effects on serum FSH and LH. One of the postmenopausal women who had an unatrophied vaginal mucosa, showed a considerable lower resorption of estrogens. There were no significant changes in the serum estrogen levels of the premenopausal women. Thus, we conclude that daily vaginal administration of 0.625 mg of conjugated estrogens for 14 days is sufficient to restore an atrophic vaginal mucosa to a premenopausal condition. Furthermore, the condition of the vaginal mucosa seems to influence the resorption, thus indicating an inbuilt mechanism of protection against overdosage of intravaginally applied estrogens.