Is the use of botulinum toxin injection for treating neurological disorders safe during pregnancy and lactation?

Botulinum neurotoxin (BoNT) is a mainstay in treating several neurological disorders including in women of reproductive age. This review, based on 43 studies encompassing 658 human cases and supporting animal data, evaluates its safety during pregnancy and lactation. Available evidence is limited and predominantly observational, with most reports describing first-trimester exposure at doses below 200 units. As a result, data on later trimesters and higher doses remain scarce. Notably, the available literature does not show an increased prevalence of fetal losses and malformations, compared to the background population rates. Evidence for BoNT use during lactation is even more limited and confined to aesthetic indications, which typically involve lower doses than those used for neurological indications. Animal studies have shown fetal toxicity only at maternally toxic doses, without teratogenic effects. These findings offer interim practical guidance on BoNT use in pregnancy and lactation. Key evidence gaps should be addressed through neurology-specific prospective studies and pregnancy registries.