Endometrial Thickness in 1,500 Asymptomatic Postmenopausal Women Not on Hormone Replacement Therapy

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.