Babies born after being exposed to both opioids and benzodiazepines before birth are more likely to have severe drug withdrawal, requiring medications like morphine for treatment, compared to infants exposed to opioids alone, according to a Vanderbilt University Medical Center study published in Hospital Pediatrics.

Benzodiazepines are a class of psychoactive drugs, including Xanax and Ativan, commonly prescribed for anxiety and other conditions. The new findings shed light on which factors complicate and intensify signs of neonatal abstinence syndrome (NAS).

People with substance use disorders often report taking a combination of substances. The study shows concurrent benzodiazepine exposure impacts the severity of NAS more so than other legal or illicit substances, said Lauren Sanlorenzo, MD, MPH, assistant professor of Pediatrics, neonatologist at Monroe Carell Jr. Children's Hospital at Vanderbilt and first author of the study.

Infants with NAS and exposed to benzodiazepines were more than 50 percent likelier to require the use of medications to treat symptoms than infants not exposed.

"Our findings reflect the reality that many women who use opioids also use benzodiazepines, which now we know has real implications for the baby, who is more likely to have severe incidence of disease. If we focus just on opioids, we can overlook other medications that can be risky to both the mother and infant," said Sanlorenzo.

Vanderbilt Center for Child Health Policy researchers have shown previously that one consequence of the nation's opioid crisis has been a sharp increase in the number of newborns who show signs of withdrawal from opioids. From 2000 to 2014, the rate of NAS rose from 1.2 cases per 1,000 hospital births to 8 cases per 1,000 births. In 2014, the average was one infant born every 15 minutes in the U.S. with NAS.