Premature infants, also called preterm infants, are babies born earlier than 37 weeks of gestation. Gestation is the number of weeks a baby spends in his mother’s womb. Full-term infants spend 40 weeks in their mother’s womb. Most premature babies are born before vital parts of the body have fully formed. This may cause different problems in their body systems, including problems with feeding, breathing, or staying warm. Your baby may need to stay in a special care unit in the hospital while he continues to grow and develop. Each premature infant may be affected differently depending on how early he was born. The earlier he is born, the higher the risk of having health problems. How is a premature infant’s age counted? The age of a baby born prematurely may be counted by the following: • Gestational age: This is the time measured from the first day of the mother’s last menstruation (monthly period). Gestational age is used to know your premature baby’s age when he was born. This also g