Emgality for Migraine in Breastmilk

Galcanezumab will be prescribed clinically by the treating clinician, i.e., no drug will be provided by the study. This treatment may be prescribed in several clinical scenarios: * Patient with established migraine history, treated with galcanezumab prior to pregnancy, who plans to resume the medication post partum * Patient with established migraine history, who experiences migraines postpartum and who has previously been "failed by", or intolerant to, other first-line prophylactic medications * Patient with established migraine history, who warrants said treatment trial otherwise, at the discretion of the prescribing clinician Interested participants will be contacted by our UCSF coordinator, sign an informed consent form, and receive instructions for milk collection. A pamphlet on effective birth control will be provided to all enrollees (https://owh-wh-d9-dev.s3.amazonaws.com/s3fs-public/documents/fact-sheet-birth-control-methods.pdf), as well as OCT-available at-home pregnancy tests. Mothers will complete questionnaires relating to their infants, at 6M and 12M postpartum (Ages and Stages, colic, etc.) and will sign a release form for us to obtain and review infant health records up to 12 months post-delivery to calculate: growth, infections, incidence of constipation or infant colic. Milk collection: Participants will pump and provide up to 8 samples (15mL volume each), at specific timepoints over up to 2 treatment cycles (before treatment 1; 24hours, 7d, 28d post treatment 1; 24hours, 7d, 28d post treatment 2 and 7d post treatment 3). Samples will be shipped in an insulated container with gel packs to maintain temperature via FedEx priority overnight shipping to our Laboratory at UCSF and stored in a -80 °C degrees freezer. Sample assays: Samples will be batch analyzed using enzyme immunoassay at (1) interim report after 15 sets received and (2) final report after all 30 sets received. The study team has worked with MarinBio who are experts in measuring biologics.