Neonatal Abstinence Syndrome

Neonatal Abstinence Syndrome (NAS), also called neonatal opioid withdrawal syndrome (NOWS), occurs when an infant who has adapted to opioid exposure before birth loses that exposure at delivery. The developing central nervous system has been repeatedly influenced by opioids; after placental transfer stops, the infant may become neurologically and autonomically overactive rather than simply “fussy.” The typical pattern is tremor, irritability, increased muscle tone, difficulty settling, poor feeding, disturbed sleep, and respiratory dysregulation. These findings do not all have to appear together. The clinically useful question is whether withdrawal is interfering with the infant’s ability to eat, sleep, or be consoled. Withdrawal is not the same as opioid toxicity. An infant with excessive opioid effect is more likely to be difficult to rouse, feed poorly because of sedation, or breathe slowly. Both conditions require attention, but giving more opioid to an infant with respiratory depression can worsen the immediate danger. Prematurity also changes the picture. A preterm infant may not display the same pattern as a term infant, and morphine may have a prolonged half-life in infants born before 34...