Breast enlargement may occur in newborn infant around the third day of life & a milky substance may come out from the nipples. This is because a burst of mother’s hormones passed to the infant shortly before delivery as a preparation for the infant’s lung to breathe air when she/he is born. This condition goes away in few days to weeks. Avoid massage or squeeze the breast to prevent infection in the breast. (http://www.drgreene.org/body.cfm?id=21&action=detail&ref=355)