Endometrial thickness in 1,500 asymptomatic postmenopausal women not on hormone replacement therapy

To determine the normal endometrial thickness (ET) on transvaginal ultrasound (TVUS) of asymptomatic postmenopausal women not on hormone replacement therapy. A subgroup that was determined to be suspicious for having an endometrial polyp was compared with the remainder.

This prospective study selected 1,500 consecutive asymptomatic postmenopausal women receiving TVUS assessment from January to August 2010. ET was recorded. Results were divided into those with a normal-appearing lining (n = 1,399) and those suspicious for polyp (n = 101). Results for the entire sample were obtained and the groups were compared using independent samples t tests.

Of 1,500 women aged 45-95 years, 77.1% had an ET of ≤4 mm and 92% were ≤5 mm. Independent samples t tests were performed to compare the mean age and mean ET based on polyp status (i.e. with or without a possible polyp). There was a significant difference in mean age, 67.71 vs. 62.36 years (p < 0.01) and mean ET 8.02 vs. 3.40 mm (p < 0.01) between groups.

92% of asymptomatic postmenopausal women not on hormone replacement therapy had an ET of ≤5 mm. The mean ET was 3.71 ± 1.9 mm. However, a significant group, 6.7%, had an endometrial lining suspicious for polyp. These women had a significant increase in mean age and ET.