Objective: To evaluate the effects of transdermal hormone replacement therapy (HRT) on uterine and leiomyoma size and on uterine bleeding patterns in postmenopausal women with uterine leiomyomas.
Methods: The required sample size was calculated to be 30 subjects per group to detect an effect on the size of one standard deviation (SD) with an alpha value of 0.05 (two-sided) and a power 1 - delta = 0.8. At the end of the study, the power analysis showed a value of beta = 0.826. Seventy postmenopausal women with uterine leiomyomas were enrolled and treated for 12 cycles of 28 days each with transdermal 17 beta-estradiol (E(2)) patches plus oral medroxyprogesterone acetate continuously added (group A) or with calcium carbonate (group B). At entry and every three cycles, uterine and leiomyoma dimensions were measured by transvaginal ultrasonography. To evaluate the effect of transdermal HRT on the characteristics of uterine bleeding, 35 healthy postmenopausal women without uterine leiomyomas (group C) were enrolled and treated with the same regimen as group A. A daily diary was used to record the abnormal uterine bleeding episodes, and a rank scale was used to assess the severity of bleeding.
Results: There were no significant changes in mean uterine or leiomyoma size between groups A and B, or in each group compared with basal values. No significant difference was detected between groups A and C in uterine bleeding patterns.
Conclusion: Transdermal HRT did not increase the size of uterine leiomyomas or affect uterine bleeding patterns in postmenopausal women.