This study of U.S. neonatal intensive care units from 2004 through 2013 showed a substantial increase over time in admissions for the neonatal abstinence syndrome and increases in associated length of stay and the percentage of NICU days nationwide attributed to the syndrome. The neonatal abstinence syndrome is a drug-withdrawal syndrome that most commonly occurs after in utero exposure to opioids. It typically manifests in the first few days of life as hypertonia, autonomic instability, irritability, poor sucking reflex, impaired weight gain, and less commonly, seizures. 1 From 2000 through 2009, the incidence of the neonatal abstinence syndrome in the United States nearly tripled, 2 with several states reporting even larger recent increases. 3 , 4 This rise occurred in association with an increase in the use of opioids by pregnant women. 5 – 8 Despite the increased incidence of the neonatal abstinence syndrome, data on changes in the . . .