The influence of reproductive factors on migraine in premenopausal women: A nationwide population-based study in South Korea

Background Sex hormones significantly impact the risk and pattern of migraine in women. Women experience various hormonal changes associated with pregnancy, childbirth, breastfeeding, and contraception. This study investigated the influence of reproductive factors on migraine in women. Methods We used the linked Korean National Health Insurance Service (KNHIS) and Korean Health Examination (KHE) databases. Reproductive factors were defined as parity, breastfeeding, and oral contraceptive use and were obtained from the KHE database. A migraine diagnosis was identified using the KNHIS database. We investigated migraine occurrence in premenopausal women between the ages of 40 and 60 years. The study population was divided into two groups depending on whether the patient was newly diagnosed with migraines during the follow-up period (2009–2018). We investigated the association between reproductive factors and migraine risk in premenopausal women. Results This study enrolled 1,059,579 premenopausal women. The risk of migraine tended to increase in the primiparous (HR: 1.175; 95% CI: 1.136–1.215) and multiparous groups (HR: 1.197; 95% CI: 1.161–1.235) compared to the nulliparous group. Breastfeeding (6–12 months, HR: 1.047; 95% CI: 1.029–1.066, and ≥ 12 months, HR: 1.104; 95% CI: 1.085–1.123) significantly increased migraine risk compared with not breastfeeding. All women in the oral contraceptive groups (