The effect of transdermal and vaginal estrogen therapy on markers of postmenopausal estrogen status

To compare serum 17beta-estradiol (E2), estrone (E1), estrone sulfate, follicle-stimulating hormone, luteinizing hormone, sex hormone-binding globulin, vaginal pH, and the vaginal maturation indices in women using a low-dose transdermal patch releasing 14 microg of E2 per day and a vaginal ring releasing 7.5 microg of E2 per day.

Twenty-four postmenopausal women were randomly assigned to either the patch (n = 12) or the ring (n = 12) for a 12-week study period. Serum E2, E1, estrone sulfate, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin were measured by immunoassay at baseline and 6 and 12 weeks. Vaginal pH was determined at baseline and 6 and 12 weeks. Vaginal cytologic examinations for vaginal maturation index were done at baseline and 12 weeks.

Twenty women completed the study. The patch significantly increased serum E1 and E2 levels at 6 and 12 weeks (P < 0.01); there was no significant increase in serum E1 and E2 levels with the ring. Both the patch and the ring significantly reduced vaginal pH at 6 (P < 0.001) and 12 (P < 0.001) weeks and significantly reduced the percentage of vaginal parabasal cells at 12 weeks with no significant difference between the two groups. Both preparations increased the proportion of superficial cells; the increase was significant only with the patch (P = 0.04).

A transdermal E2 skin patch releasing 14 microg of E2 per day had an effect on vaginal pH and vaginal maturation indices similar to that of a vaginal E2 ring releasing 7.5 microg of E2 per day. Therefore, this patch is likely to relieve symptoms of vulvovaginal atrophy.