RELATIONSHIP BETWEEN CIRCULATING ESTRADIOL LEVELS, BODY-MASS INDEX, AND BREAKTHROUGH BLEEDING IN POSTMENOPAUSAL WOMEN RECEIVING HORMONE REPLACEMENT THERAPY

Objective: The purpose of this prospective study was to investigate th e association of breakthrough bleeding with circulating estradiol leve ls and obesity in postmenopausal women receiving hormone replacement t herapy. Design: Fifty postmenopausal women receiving 0.625mg conjugate d estrogen with 2.5mg medroxyprogesterone acetate were included in the study. Patients are recalled at Ist, 5th and 9th weeks for the measur ements of the serum estradiol levels. Results: Twenty women (40%) had a bleeding episode within 9 weeks of therapy. Of the 25 women who had a body mass index (BMI) of >25, 13 (52%) had bleeding. Of the 25 women who had a BMI of <25, 7 (28%) had bleeding. There was a trend toward a relation between BMI and breakthrough bleeding, although the relatio n did not achieve significance (p = 0.14). Serum estradiol levels of b oth bleeders and nonbleeders remained similar throughout the study. En dometrial histology revealed proliferative endometrium in two cases an d secretory endometrium in one case at baseline; two cases of prolifer ative endometrium were found during bleeding. The remaining samples re vealed atrophy. Conclusions: No relation was found between serum estra diol levels and breakthrough bleeding. Nevertheless, increased BMI may have an impact on breakthrough bleeding in postmenopausal women recei ving hormone replacement therapy.