Transvaginal ultrasonographic assessment of the endometrium in asymptomatic, postmenopausal women using different HRT regimens containing tibolone or estrogen.

OBJECTIVE

To assess the effects of hormone replacement therapy (HRT) on endometrial thickness as measured by transvaginal ultrasonography in asymptomatic, postmenopausal women.

STUDY DESIGN

Between 1997 and 2001, 307 women who had no risk factors for endometrial cancer or abnormal vaginal bleeding were enrolled in a study. Patients received 1 of the following HRT modalities: (1) oral equine HRT modalities: (1) oral equine estrogen, (2) oral 17beta-estrogen, (3) transdermal 17beta-estrogen, or (4) oral tibolone. All women taking estrogens were also taking a progestin. Only the patients with endometrial thickness >7 mm underwent endometrial biopsy while taking HRT.

RESULTS

Although we observed an increase in serum estrogen levels as compared to the levels before tibolone therapy, changes in endometrial thickness were not statistically significant in patients taking tibolone.

CONCLUSION

Endometrial thickness with tibolone closely mimics the naturally atrophic postmenopausal state. Thus, tibolone is suggested for those postmenopausal women who have concerns about HRT.