Changes in Endometrial Thickness in Postmenopausal Women During Hormone Replacement Therapy

Choi, Young Min; Kim, Eun Kyong; Ku, Seung Yup; Suh, Chang Suk; Kim, Seok Hyun; Kim, Jung Gu; Moon, Shin Yong; Lee, Yong Hee; Lee, Jin Yong

Abstract

OBJECTIVE
The purpose of this study was to evaluate the effect of hormone replacement therapy on endometrial thickness in postmenopausal women and to assess the difference in endometrial thickness by the type of hormone replacement therapy (HRT). MATERIALS AND METHODS: Endometrial thickness was measured in 258 postmenopausal women before and/or during 12 months of HRT. The subjects were grouped into the sequential therapy group (Group 1, 72 women) and continuous combined therapy group (Group 2, 186 women). Group 1 received 0.625 mg of conjugate equine estrogen (CEE) daily with cyclic addition of medroxyprogesterone acetate (MPA, 10 mg/day for 12 days per month). Group 2 received 0.625 mg of CEE with daily addition of MPA (2.5 mg/day).
RESULTS
The sequential group showed no significant change in endometrial thickness during HRT compared to that before HRT. However, a significant increase in endometrial thickness was found in the continuous combined group at 12 months of treatment. Before HRT, the endometrial thickness in the continuous combined group was thinner than that of the sequential group. During 12 months of treatment, there was no difference in endometrial thickness between the types of HRT. And the proportion of patients with endometrial thickness of 8mm or greater at 12 months of treatment did not differ significantly from that before treatment in both groups.
CONCLUSION
Sequential HRT did not influence the endometrial thickness during treatment. However, continuous combined HRT increased the endometrial thickness during 12 months of treatment compared to that before treatment. The different endometrial responses to each HRT regimen may be due to the difference in endometrial thickness before treatment in each group.