Neonatal withdrawal or neonatal abstinence syndrome (NAS) or neonatal opioid withdrawal syndrome (NOWS) is a drug withdrawal syndrome of infants, caused by the cessation of the administration of drugs which may or may not be licit. Tolerance, dependence, and withdrawal may occur as a result of repeated administration of drugs, or after short-term high-dose use—for example, during mechanical ventilation in intensive care units. There are two types of NAS: prenatal and postnatal...