What kind of blood do they give to a newborn if needed?

Packed matched cells. Premi's or newborns blood needs vary with the issue being treated. If it is simple anemia created by the need for frequent blood tests, type specific, washed, packed cells (high density, low serum volume) are normally used. Occasionally with high bilirubin levels may lead to an exchange transfusion with regular blood.
Matched. Blood. Just like an adult infants have the major blood groups of o, a, b, and ab, as well as minor antigens, therefore blood has to be matched appropriately. In addition blood is typically irradiated and has white blood cells removed, to prevent reactions and infection. If your child is premature the also may avoid cmv+ blood. Parents also can frequently donate. Blood for their child if you desire.
Blood transfusion. The hospital may give the baby o neg blood or blood that is the same type of the infant.
See below. They will give blood that matches the infants blood type if any is needed.