High prescribing rates of opioid painkillers are likely a factor in the increase in neonatal abstinence syndrome, according to the head of the National Institute on Drug Abuse.

Dr. Nora Volkow wrote in this week’s British Medical Journal that between 2000 and 2009, the incidence of neonatal abstinence syndrome among newborns increased from 1.2 to 3.4 per 1,000 live births.

An estimated 14 percent to 22 percent of pregnant women in the United States are prescribed opioid painkillers, HealthDay reports. There have been reports of an increase in the rate of painkiller abuse among pregnant women, the article notes.

Babies born with neonatal abstinence syndrome undergo withdrawal from the addictive drugs their mothers took during pregnancy, such as oxycodone, morphine or hydrocodone. The syndrome affected seven babies for every 1,000 admitted to a neonatal intensive care unit in 2004. That number jumped to 27 infants per 1,000 by 2013.

Opioid use during pregnancy could theoretically disrupt attachment between women and their babies, she said. “Cognitive impairments have also been reported in children and young people born to women who misused opioids during pregnancy, although the relative contributions of other drugs or lifestyle factors to such deficits are unclear,” Dr. Volkow wrote.

Painkiller prescriptions for pregnant women should be restricted to those who suffer from severe pain that cannot be controlled with other treatments, and should only be used for a short period, she recommended.

Women who require long-term use of opioids, such as those being treated with buprenorphine or methadone maintenance therapy for heroin addiction, should be carefully assessed and monitored to reduce their risk of misuse, overdose and drug withdrawal syndrome in their infants, she said.