Prevalence of endometrial polyps and abnormal uterine bleeding in a Danish population aged 20–74 years

OBJECTIVE: To estimate the prevalence of endometrial polyps and to investigate associated abnormal uterine bleeding in a Danish population aged 20-74 years. METHODS: This was a study of a random selection of women from the Danish Civil Registration System: 1660 women were invited of whom 686 were included (429 pre- and 257 postmenopausal). AUB was assessed by a validated questionnaire. The women underwent transvaginal sonography (TVS) and saline contrast sonohysterography (SCSH). Hysteroscopic resection was performed in cases with suspected focal intrauterine pathology. Full evaluation was performed in 619 women (two failures of TVS and 60 failures of SCSH, in two women SCSH was contraindicated (endometrial cancer), in two women hysteroscopy was contraindicated, and one polyp was lost before histology). World Health Organization histopathological criteria were used for diagnosing true endometrial polyps. RESULTS: On final diagnosis there were 48 women with polyps, eight with submucosal myomas, four with other benign findings and one with polypoidal growing endometrial cancer. Complex hyperplasia without atypia was diagnosed in two women with polyps. The prevalence of endometrial polyps was 7.8% (48/619; 95% CI, 5.6-9.9%). The prevalence was influenced significantly by age (P<0.005); in women below the age of 30 years, the prevalence was 0.9%. Polyps were diagnosed in 5.8% of pre- and 11.8% of postmenopausal women (P<0.01). Thirty-nine (82%) of the women who had histopathologically verified polyps were asymptomatic. In asymptomatic premenopausal women the prevalence of polyps was 7.6%, while it was 13% in asymptomatic postmenopausal women. AUB, in particular intermenstrual bleeding, was more frequent among women without polyps (38%). By ultrasound examination, submucosal myomas were diagnosed in 4.2% (26/622; 95% CI, 2.6-5.8%) and intramural myomas in 11.1% (76/684; 95% CI, 8.8-13.5%) of women. Polyps were diagnosed in 2% of oral-contraceptive and 25% of hormone-therapy users. CONCLUSIONS: The overall prevalence of endometrial polyps was 7.8% and the prevalence increased with age. Polyps were rare (0.9%) in women below the age of 30 years. Surprisingly, AUB was less frequent among women with polyps than among those without polyps.