The Safety of OnabotulinumtoxinA (OnabotA) During Pregnancy and Breastfeeding: Implications for Chronic Migraines.

BACKGROUND AND OBJECTIVES: A migraine is a highly prevalent and disabling neurological disorder that mainly affects women of childbearing age. Treatment options for migraine prevention are limited during pregnancy and breastfeeding. Although OnabotulinumtoxinA (OnabotA) has proven efficacy and safety in chronic migraine prophylaxis in adults, its safety in pregnancy and breastfeeding remains understudied. METHODS: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology, this review systematically appraised the evidence on the use of OnabotA for chronic migraines and other neurological conditions during pregnancy and breastfeeding across four electronic databases between January 2000 and December 2025. RESULTS: In summary, of the 555 OnabotA-exposed pregnancies, 80.2% resulted in full-term births, with a 17.5% loss rate (73 spontaneous, 21 elective, three unspecified) and 1.6% reporting foetal anomalies. These findings align with general population baselines for miscarriages (12.5-18.7%) and foetal anomalies (3-5%), respectively. Among 94 cases of reported breastfeeding, no adverse infant events or developmental delays were observed at 1 year. Maternal outcomes showed favourable symptom control without adverse effects. CONCLUSIONS: Although there is limited data on the use of OnabotA in pregnancy and breastfeeding, no significant adverse effects have been identified in pregnant mothers or neonates. OnabotA should therefore be considered on a case-by-case basis for treatment of various neurological conditions, including migraines, when there are no better safe alternatives.