The number of pregnant women with opioid use disorder (OUD) at labor and delivery more than quadrupled between 1999 and 2014, to 6.5 per 1,000 hospital births, according to a new analysis by the Centers for Disease Control and Prevention. State rates in 2014 varied widely, from 0.7 per 1,000 in Washington, D.C. to 48.6 per 1,000 in Vermont. The variance may reflect differences in opioid prescribing rates and illicit drug use as well as improved screening, diagnosis and treatment for OUD and neonatal abstinence syndrome, the report notes.