Little is known about factors associated with migraine pharmacotherapy during pregnancy. Of 60 435 pregnant women in a population-based cohort, 3480 (5.8%) reported having migraine during the first 5 months of pregnancy. Of these, 2525 (72.6%) reported using migraine pharmacotherapy, mostly non-narcotic analgesics (54.1%) and triptans (25.4%). After adjustment for sociodemographic factors and comorbidities in logistic regression analysis, high pregestational body mass index [odds ratio (OR) 1.3, 95% confidence interval (CI) 1.2, 1.4], sleep < 5 h (OR 1.6, 95% CI 1.3, 1.9), being on sick-leave (OR 1.3, 95% CI 1.2, 1.5) and acute back/shoulder/neck pain (OR 0.6, 95% CI 0.6, 0.7) were associated with migraine pharmacotherapy during pregnancy. Many women need drug treatment for migraine during pregnancy, and the choice of pharmacotherapy during this period may be influenced by maternal sociodemographic factors and comorbidities.