To the Editor: The article by Dr Patrick and colleagues1 provides important data on US trends in maternal opioid use, neonatal abstinence syndrome (NAS), and NAS-associated hospital costs. These findings should spark forward-thinking research. However, certain cautions regarding the results must be considered.
Future research should focus on the relationship between diagnostic groups (eg, mothers with long-term methadone use) and neonatal outcomes, including but not limited to NAS. Different outcomes—with quite different costs—may occur for neonates of women who are untreated or misusing opioids vs those maintained on opioid agonists or medicated for pain. While many of the clinical conditions in Table 1 of the article may occur in infants born to methadone-stabilized women, their frequency in infants born to methadone-stabilized women is lower2 than the frequency reported for all infants born with NAS.