Endometrial thickness and uterine diameter not affected by ultralow doses of 17β-estradiol in elderly women

Objective: Our purpose was to monitor changes in endometrial thickness and uterine diameter during treatment with ultralow doses of estradiol, which might improve the serum lipid profile in elderly women. Study Design: Ultrasonographic changes were monitored in 60 women with an intact uterus in a group of 70 healthy women who were previously evaluated for changes in serum lipid levels. Subjects were 60 years and older and were randomly assigned to receive parenteral 17β-estradiol (7.5 μg/24 h), delivered by a vaginal ring (Estring; Pharmacia-Upjohn, Malmö, Sweden), or no treatment for 12 months. Results: Estring treatment yielded minor increases in serum estrone sulfate and 17β-estradiol levels within the normal postmenopausal range. The maximal endometrial thickness was 2.8 mm at baseline and 2.6 mm at 12 months. No significant changes within or between the study groups were found in endometrial thickness or uterine diameter. There were no significant interactions between age and baseline serum estrone sulfate or 17β-estradiol levels. Conclusions: Ultralow doses of 17β-estradiol, which might improve serum lipid levels, did not significantly change endometrial thickness or uterine diameter. This might indicate that there is a “therapeutic window” for systemic effects of ultralow doses of estradiol in elderly women without any apparent increase in endometrial thickness. (Am J Obstet Gynecol 2002;186:944-7.)