A new study finds a woman's use of prescription opioids during pregnancy increases the risk her baby will be born small or early.
Such use also raises the chance the baby will go through painful drug withdrawal, known as neonatal abstinence syndrome, HealthDay reports.
The study of more than 112,000 pregnant women in Tennessee found almost 28 percent used at least one prescription opioid, such as hydrocodone or oxycodone.
The risks to the baby increased if a woman also smoked or took antidepressants, the researchers report in Pediatrics.
Of the babies with neonatal abstinence syndrome, 65 percent had mothers that legally filled prescriptions for opioid pain relievers.
"Historically, drug withdrawal for newborns has been described among illicit drug use such as heroin or women treated for previous opioid abuse, but this is really one of the first studies to look at legal prescriptions for pregnant women," lead author Dr. Stephen Patrick of Vanderbilt University in Nashville said in a news release.
The study found 42 percent of the women prescribed opioids smoked during pregnancy, compared with 26 percent of the women not prescribed opioids. The more cigarettes a woman smoked each day, the more likely she was to give birth to a baby with neonatal abstinence syndrome.
Taking a type of antidepressant called selective serotonin reuptake inhibitors along with prescription opioids also doubled the risk of the syndrome. "Infants with neonatal abstinence syndrome have longer, more complicated birth hospitalizations," Patrick said.
Babies with neonatal abstinence syndrome were twice as likely to be born with a low birth weight, and were much more likely to have respiratory problems, feeding difficulties and seizures, compared with babies without the syndrome.