Reproductive factors and the risk of pelvic organ prolapse in postmenopausal women: A nationwide cohort study.

OBJECTIVE

To examine associations between reproductive factors and the risk of pelvic organ prolapse in postmenopausal women.

STUDY

DESIGN

This nationwide retrospective cohort study included postmenopausal women aged 40 to 79 years who participated in a national health screening program in the period 2009-2012 in Korea. Participants were followed until 2022.

MAIN OUTCOME MEASURES: Clinically treated pelvic organ prolapse, defined by concurrent diagnosis and procedure codes (surgery or pessary).

RESULTS

Among 3,743,520 women, 34,792 (0.9%) developed pelvic organ prolapse during a median follow-up of 10 years, corresponding to an incidence rate of 938 per 100,000 person-years. In fully adjusted models, having two or more births was the strongest predictor of pelvic organ prolapse (hazard ratio 1.751; 95% confidence interval 1.561-1.963). Breastfeeding ≥12 months (hazard ratio 1.297; 95% confidence interval 1.228-1.369), oral contraceptive use ≥1 year (hazard ratio 1.067; 95% confidence interval 1.024-1.112), menopausal hormone therapy for 2-4 years (hazard ratio 1.083; 95% confidence interval 1.022-1.147), age at menopause ≥55 years (hazard ratio 1.064; 95% confidence interval 1.031-1.098), and reproductive span ≥40 years (hazard ratio 1.169; 95% confidence interval 1.112-1.229) were each modestly associated with increased risk of pelvic organ prolapse. Age at menarche showed no association. Trends across exposure categories were significant for all factors except menarche. In women with parity 0 or 1, most reproductive factors were unrelated to pelvic organ prolapse, but prolonged breastfeeding (≥12 months) had a significant association (hazard ratio 1.348; 95% confidence interval 1.164-1.561).

CONCLUSION

Having multiple births and prolonged breastfeeding are key independent risk factors for pelvic organ prolapse in postmenopausal women. Other reproductive and hormonal factors have only minor effects.