Neonatal nursing is a subspecialty of nursing that works with newborn infants born with a variety of problems ranging from prematurity, birth defects, infection, cardiac malformations, and surgical problems. The neonatal period is defined as the first month of life; however, these newborns are often sick for months. Neonatal nursing generally encompasses care for those infants who experience problems shortly after birth, but it also encompasses care for infants who experience long-term problems related to their prematurity or illness after birth. A few neonatal nurses may care for infants up to about 2 years of age. Most neonatal nurses care for infants from the time of birth until they are discharged from the hospital.