The goal of this project is to evaluate galcanezumab transfer into maternal breastmilk, and to evaluate infant (growth, development, constipation, colic, infections) and maternal (headache) outcomes for dyads in which the mother was treated with galcanezumab and to compare outcomes for infants who were or were not breastfed after maternal treatment. In this prospective observational study, the study team proposes to prospectively collect serial milk samples from 30 adult women who are treated with galcanezumab for migraine. Mothers who are interested in participating will be connected with us, the main clinical site, by neurologists across the USA. Mothers must carry a diagnosis of migraine, be aged 18-45 years, and be between 14 days and 9 months postpartum, and still nursing, at the time of enrollment. This study will fill a significant unmet need as women of childbearing potential are over-represented in the migraine population, and yet they are excluded from clinical trials of migraine treatments during pregnancy and lactation.