Research presented at the American Headache Society Annual Meeting indicates that calcitonin gene‑related peptide (CGRP) monoclonal antibody injections, a leading preventive therapy for severe migraine, are associated with a 45% increase in miscarriage risk when used between weeks eight and twelve of pregnancy. the analysis covered 7,579 pregnancies among 7,119 women aged 15‑45 who had a pre‑existing migraine diagnosis.

45% higher miscarriage risk linked to CGRP antibodies

The study found that women who received CGRP monoclonal antibodies during early pregnancy experienced a miscarriage rate of 5%, compared with a 2% rate among those taking propranolol and an even lower rate for women not on any migraine medication. According to the researchers, this translates to a 45% relative increase in risk.

Five‑month drug half‑life fuels safety concerns

One of the key pharmacological issues highlighted is the long persistence of these injectable biologics ; the drugs can remain in the bloodstream for up to five months after the last dose. As the report notes, this lingering presence means that an unplanned conception can still be exposed to therapeutic levels of the antibody, even if the patient stops treatment well before trying to become pregnant.

NHS guidance already bans CGRP use in pregnancy

Current NHS advice advises against prescribing CGRP monoclonal antibodies to women who are pregnant, planning to conceive, or breastfeeding. The new findings reinforce that guidance, with experts urging clinicians to intensify pre‑conception counseling and to discuss alternative migraine therapies such as propranolol, which showed a lower miscarriage rate in the same cohort.

What long‑term outcomes for children exposed in utero?

The study did not track developmental or health outcomes for infants born after maternal exposure to CGRP antibodies, leaving a gap in the safety profile. Independent specialists cited in the report call for longitudinal research to determine whether in‑utero exposure could affect neurodevelopment or other health markers later in life.

Who should patients talk to before stopping treatment?

Clinicians, particularly neurologists and primary‑care physicians, are urged to coordinate with obstetricians when a woman on CGRP therapy expresses a desire to become pregnant. According to the investigators ,a multidisciplinary approach can help balance migraine control with reproductive safety.