Transvaginal ultrasonographic measurement of endometrial thickness in postmenopausal women receiving estrogen replacement therapy

OBJECTIVE: This study was undertaken to evaluate endometrial thickness by transvaginal ultrasonography in asymptomatic postmenopausal women receiving estrogen replacement therapy. The endometrial thickness in this study group was compared with endometrial thickness measurements in a group of women who had abnormal postmenopausal bleeding. The recent literature was reviewed. STUDY DESIGN: Asymptomatic postmenopausal women receiving estrogen replacement, seen for routine examination during the 1-year period from Jan. 1, 1994, to Dec. 31, 1995, had the endometrium evaluated by transvaginal ultrasonography. Women with abnormal postmenopausal bleeding were likewise evaluated and their measurements compared with those of the study group. RESULTS: Twenty-seven different estrogen and estrogen-progestin combinations in 327 asymptomatic women were studied. Additionally, 24 women who were bleeding, not receiving estrogen, and 46 women with abnormal bleeding on estrogen therapy underwent ultrasonography of the endometrium. Endometrial thickness ranged from 1 to 15 mm in women on a regimen of combined estrogen-progestin therapy, 1 to 14 mm in women using sequential estrogen-progestin, and 3 to 15 mm for women receiving unopposed estrogen in the study group. For women with abnormal bleeding not using estrogen, the endometrium measured an average of 12.3 mm (range 2 to 29 mm), with unopposed estrogen 8.3 mm (range 4 to 13 mm), and for estrogen with progestin 6.5 mm (range 2 to 15 mm). Significant pathologic features were found in those women who had bleeding and endometrial measurements between 5.0 and 29 mm. CONCLUSION: There was no significant difference between endometrial thickness measurements in women receiving various combinations of estrogen replacement. In general, expected endometrial measurements can range from 1 to 15 mm. In women with postmenopausal bleeding, however, significant pathologic features may exist with an endometrium measuring as little as 5 mm. (Am J Obstet Gynecol 1997;176:1334-9.)