Overview
The Newborn Transition
Birth removes the placenta as the source of oxygen, glucose, and temperature control.
Birth removes the placenta as the source of oxygen, glucose, and temperature control. The infant must establish effective breathing, increase pulmonary blood flow, redirect circulation away from fetal shunts, maintain body temperature, and begin independent glucose regulation within minutes. The first breath expands fluid-filled alveoli. As pulmonary vascular resistance falls, blood moves through the lungs for oxygenation rather than being preferentially diverted through the foramen ovale and ductus arteriosus. Surfactant helps keep the alveoli open; inadequate surfactant, especially in a preterm infant, increases the risk of atelectasis and respiratory distress. This transition is judged by the infant's actual breathing and circulation, not by appearance alone. A newborn who is apnoeic, gasping, persistently bradycardic, hypotonic, or centrally cyanosed needs immediate assessment and support. Apgar scoring at one and five minutes documents the response to extrauterine life; it does not replace assessment of heart rate, respiratory effort, and tone or delay resuscitation. Gestational age changes the risk profile. Late-preterm infants may look nearly mature yet have less reliable temperature control, feeding coordination, respiratory adaptation, and bilirubin clearance. Maternal diabetes, suspected infection, prolonged...
