Objective: To determine the association between endometrial thickness and endometrial histology in a large sample of women using HRT.
Design: Results from three multi-centre studies were combined.
Participants: Five hundred and sixty-four climacteric women were treated with either sequential, continuous combined or long-cycle therapy.
Main outcome measures: The women underwent 717 examinations with both transvaginal ultrasonography and histological examination of the endometrium. Endometrial thickness was measured and associated with the histological findings.
Results: Eight cases of endometrial hyperplasia were diagnosed. All the hyperplasias were simple without atypia. Two cases had an endometrial thickness < 4 mm and two a thickness > 8 mm. The > 4 mm threshold for abnormal endometrium had a sensitivity of 75%, a specificity of 47%, a positive predictive value of 2% and a negative predictive value of 99%.
Conclusion: No association could be found between the endometrial thickness measured by transvaginal ultrasonography and endometrial pathology. In six out of eight women with simple hyperplasia the endometrium measured > 4 mm.