Anti-CGRP Migraine Drugs Linked to 42% Higher Miscarriage Risk
A large U.S. study found pregnant women using anti-CGRP monoclonal antibodies for migraine prevention had a 42% higher risk of spontaneous abortion compared to nonusers, while propranolol showed no increased risk.
Pregnant migraineurs exposed to anti-CGRP monoclonal antibodies had a 42% higher risk of spontaneous abortion compared to nonusers. The findings, from a study of over 7,100 pregnancies, provide the first large-scale evidence on the safety of these newer preventive drugs during pregnancy.
Within the first 20 weeks of pregnancy, there was about a 40% higher chance of miscarriage among mothers exposed to anti-CGRP monoclonal antibody therapy. The study analyzed 7,579 singleton pregnancies from 2018 to 2021 using U.S. private health insurance data. Women in the sample had been diagnosed with migraine or prescribed related drugs in the six months before their last menstrual period.
A total of 1,862 spontaneous abortions occurred during the study period. This included 100 spontaneous abortions during anti-CGRP exposed person-time and 37 during propranolol-exposed person-time.
Propranolol shows no increased risk, supporting current guidelines
In contrast, propranolol use was not associated with increased miscarriage risk. Women who used this older beta-blocker for migraine prevention did not have this raised risk. The adjusted hazard ratio was 1.02.
This aligns with current clinical recommendations. Our findings are in line with the current guidelines on migraine preventive therapies, which recommend discontinuation of anti-CGRP at least 5 months before conception and switching to established migraine preventive therapies such as propranolol, the authors noted. Propranolol is considered a first-line preventive treatment.
Study details and limitations highlight need for caution
The research was a retrospective cohort analysis published in JAMA Neurology on October 12, 2026. It used data from the AM-PREGNANT cohort, built from the Merative MarketScan commercial database. The cohort included 7,119 women with pregestational migraine with a mean age of 31.6 years.
| Drug Exposure | Number of Pregnancies | Associated Miscarriage Risk (Adjusted Hazard Ratio) |
|---|---|---|
| Anti-CGRP monoclonal antibodies | 350 | 1.42 (95% CI 1.12-1.80) |
| Propranolol | 283 | 1.02 (95% CI 0.71-1.47) |
| No exposure | 6,946 | Reference (1.00) |
The study design was observational and cannot establish causation, only association. Lead researcher Anick Bérard, PhD, stated: "Our study is the first large-scale study looking at the safety of anti-CGRP during pregnancy for the prevention of chronic migraine."
Several limitations were noted. Insurance records may not capture migraine severity, medication adherence, or whether pregnancies were planned. The study did not confirm whether prescribed medicines were actually taken. The sample was also limited to commercially insured individuals in the United States, which limits generalizability.
CGRP antibodies are used to prevent migraines, including for patients who do not respond to common oral medications. Clinicians should consider the limited pregnancy safety evidence when discussing anti-CGRP monoclonal antibody treatment with individuals who may become pregnant.
