The lungs are now responsible for continuously bringing oxygen into the blood and eliminating carbon dioxide. Most newborns have no difficulty in establishing the first effective breaths which trigger this sequence of changes. If an infant cannot initiate and sustain effective breathing after birth, or if the placenta has malfunctioned before birth, oxygen and carbon dioxide cannot be adequately exchanged resulting in a dangerous drop in the infant's blood oxygen level accompanied by an increase in the carbon dioxide level and accumulation of acid. If not quickly corrected, the heart will weaken and the heart rate will dangerously slow, preventing an adequate amount of blood from reaching the organs, especially the brain. The organs, most importantly the brain, may be damaged, sometimes irreparably.
Perinatal asphyxia occurs in both premature and term infants.
Generally, if the asphyxial episode is mild, infants show no evidence of permanent injury to the brain and no long-term developmental problems. However, if the asphyxial episode is severe, an infant may die, or survive with life-long neurologic disabilities, including cerebral palsy, mental retardation, vision and hearing impairments, and learning disabilities. Such problems may not necessarily show up until the infant is older, necessitating the need for long-term monitoring. Any infant who has experienced perinatal asphyxia should receive special developmental follow-up for the first few years of life. The goal of developmental follow-up for asphyxiated infants is the identification of potential neurologic and developmental problems with referral to appropriate interventional therapies at the earliest possible age.