^BPremature baby. ^bView of a premature baby in an incubator with a respirator over its nose. The incubator provides the baby with the ideal environment for survival. Premature babies are those born before the normal 37 weeks of gestation has elapsed. Characteristically they have wrinkly features, downy hair called lanugo, irregular breathing and an inability to swallow. The respirator ensures that the baby is receiving sufficient oxygen. Premature babies are usually kept in hospital until they weigh about 2.25 kg and are feeding well.