Maternal vedolizumab injections appear to produce low levels in breastmilk and to not adversely affect the nursing infant. Because vedolizumab is a large protein molecule with a molecular weight of about 147,000 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] Additionally, vedolizumab does not affect SIgA, SIgM levels in milk in women with inflammatory bowel disease. Most experts and guidelines consider vedolizumab to be probably acceptable during nursing.[3-6] Until more data become available, vedolizumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.[7]