This multicenter MAT-LINK analysis examined how different case definitions identify neonatal abstinence syndrome or neonatal opioid withdrawal syndrome among infants born to patients with opioid use disorder. Estimated prevalence varied markedly by definition, from 47.2% using diagnosis codes to 85.9% using a standardized surveillance definition. Diagnostic codes alone missed infants identified through clinical signs or other records. The authors recommend improving documentation of withdrawal signs, substance exposure, and clinical diagnoses to support surveillance and follow-up. Results from specialized treatment sites may not generalize to all birth settings.
