Both the number of US infants diagnosed with neonatal opioid withdrawal syndrome (NOWS) and infants entering US foster care have grown substantially since 2009. A new study, released ahead of print by Health Affairs, seeks for the first time to determine whether the two have an association and whether other county-level factors were also related to infant foster care rates. According to the authors, an increase of one NOWS diagnosis per ten births in the county was associated with a 41 percent higher rate of infant foster care entry. The authors found that county rurality was associated with a 19 percent higher rate of foster care and that a higher employment rate was associated with a lower foster care rate overall and in urban counties. To reach their conclusions, the authors analyzed data from 580 counties in eight US states (New York, Kentucky, Washington, Florida, Massachusetts, Tennessee, North Carolina, and Michigan) for 2009–17.