Relation between pelvic organ prolapse and menopausal hormone therapy: nationwide cohort study

To analyze the relationship between pelvic organ prolapse (POP) and menopausal hormone therapy (MHT). This retrospective cohort study used Korean National Health checkup and insurance data from 2002 to 2019. The MHT group consisted of women who were prescribed menopausal hormones for more than 6 months from 2002 to 2011. The non-MHT group comprised postmenopausal women who had never used MHT. In the non-MHT group, there were 1,001,350 women, while the MHT group had 353,206 women. Tibolone (adjusted hazard ratio [aHR], 0.87; 99% confidence interval [CI], 0.818-0.926) and combined estrogen plus progestin by the manufacturer (CEPM) (aHR, 0.821; 99% CI, 0.758-0.89) were associated with reduced POP risk. The other oral MHT groups and the transdermal estrogen group showed no significant difference in POP risk compared with the non-MHT group (other oral MHT: aHR, 1.045; 99% CI, 0.941-1.161) (transdermal estrogen: aHR, 1.252; 99% CI, 0.731-2.145). Lower body mass index (BMI) (<18.5) was associated with reduced POP risk (aHR, 0.822; 99% CI, 0.698-0.968), while a BMI between 23 and 29.9 was associated with increased risk (BMI 23-24.9: aHR, 1.143; 99% CI, 1.088-1.2) (BMI 25-29.9: aHR, 1.173; 99% CI, 1.12-1.228). All parities had a higher POP risk than parity 1 (parity 0 or no response: aHR, 1.785; 99% CI, 1.589-2.005; parity 2: aHR, 1.434; 99% CI, 1.292-1.592; parity ≥3: aHR, 1.916; 99% CI, 1.712-2.144). After menopause, tibolone and CEPM were associated with a reduced POP risk compared with non-MHT. Other oral MHT and transdermal estrogen were not associated with the risk of POP.