A comparative study of transvaginal uterine ultrasound and endometrial biopsy for evaluating the endometrium of postmenopausal women taking hormone replacement therapy

Objective: Compare transvaginal uterine ultrasound and endometrial biopsy i n evaluating the endometrium of postmenopausal women who are taking estroge n replacement therapy (ERT) or hormone replacement therapy (HRT; estrogen a nd progestin). Design: Prospective multicenter study done in the United States with 148 he althy women with an intact uterus, A total of 121 women used hormonal prepa rations prescribed by personal physicians. Continuous combined HRT regimens , nonoral forms of ERT or HRT, and intrauterine devices were not allowed fo r 3 months before the study began. Endometrial biopsy samples were taken wi thin 3 days of transvaginal ultrasound measurement. The uterus was scanned transversely and longitudinally. Endometrial thickness was measured at the thickest part of the longitudinal plane. Results: Endometrial thickness ranged from 1.0 to 25.0 mm. The range in 126 women with a normal endometrium (determined by diagnoses of endometrial bi opsies) was 1.0-25.0 mm (median, 5.0 mm); in 15 women with an abnormal endo metrium, the range was 2.8-23.0 mm (median, 6.2 mm). A significant differen ce (p = 0.006) in endometrial thickness was seen between the 38 subjects ta king ERT and HRT (median, 6.1 mm) with unexpected bleeding or spotting and the 26 untreated women in the control group (median, 4.0 mm), Overall, resu lts were clinically inconclusive. Conclusions: Results of ultrasound as a screening technique in postmenopaus al women who were taking ERT or HRT did not correlate well with results of endometrial biopsy. Unscheduled bleeding in postmenopausal women should be investigated regardless of results of ultrasono-graphically determined endo metrial thickness. Abnormalities may be found with an endometrial thickness of less than 4 mm with or without HRT and even with no bleeding. (C) 1999, The North American Menopause Society.