Whether your baby is breast or formula fed, the American Academy of Pediatrics recommends an oral Vitamin D supplement (400 IU) daily.
Breastfed babies should continue taking this daily supplement until they have other dietary sources of Vitamin D, which usually means after a year of age. Formula fed babies need to continue the vitamin supplements until they are drinking at least 32 oz of formula daily (around 4 months of age). Why? Vitamin D is essential for healthy bone growth. Most breast milk is deficient in Vitamin D and for most infant formula preparations, babies need to take a large enough daily volume to get the appropriate amount of Vitamin D from it. There are a variety of baby Vitamin D drops on the market. We typically recommend D-Vi-Sol because it is easy to find and is strictly Vitamin D (not a multivitamin).