Reflux or Milk spits common on newborn till few months old. Baby's oesophagus yet to be fully developed, hence milk content will flow up back causing milk spits or reflux. It is also important to burp in up right position after feeding. This is to ensure baby's don't feel bloated/gassy after feeding. Be it BM/FM intake do ensure baby burp before putting them to bed (take time and do not rush to burp them neither putting them to bed)