No information is available about vilobelimab during breastfeeding. Because vilobelimab is a large protein molecule with a molecular weight of about 149,000 Da, the amount in milk is likely to be very low.[1] It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal.[2] The manufacturer recommends that breastfeeding be discontinued during vilobelimab use. The half-life of vilobelimab is about 4 days, so it should be mostly eliminated about 2 weeks after the last dose. If the mother is at least 2 weeks postpartum the transfer into milk may be minimized.[3]