Use of prescription narcotic painkillers is common in pregnancy and increases the likelihood a baby will be born small or early, or go through painful drug withdrawal, a new study finds.
These prescription painkillers, also called opioids, include drugs such as hydrocodone (Vicodin), oxycodone (Oxycontin), codeine and morphine. Nearly 30 percent of the Tennessee mothers-to-be in the new study used at least one of these drugs while pregnant, and the associated risks went up if they also smoked or took antidepressants.
"I was surprised by the number of women prescribed opioid pain relievers in pregnancy," said lead author Dr. Stephen Patrick, a neonatologist and assistant professor of pediatrics at Vanderbilt University in Nashville. "I was also surprised by how commonly women smoked in pregnancy, and how much that increased the risk of neonatal abstinence syndrome among those who also used opioid pain relievers in pregnancy."
Neonatal abstinence syndrome is a collection of problems suffered by newborns exposed to addictive drugs in the womb.
With rates of prescription painkiller abuse surging in the United States in recent years, experts have been increasingly concerned about potential effects on newborns. Past research has shown the percentage of women taking prescription painkillers during pregnancy has doubled over the past 15 years.
For the new study, published online April 13 in the journal Pediatrics, researchers analyzed the medical records of more than 112,000 women on the Tennessee Medicaid program between 2009 and 2011. Of these, about 28 percent filled a prescription for at least one narcotic painkiller.
The vast majority took short-acting medications, such as hydrocodone or oxycodone. Only 3 percent were on maintenance therapy for addiction to illegal narcotics, such as heroin.
"Some women need to take opioids in pregnancy to improve their infant's outcome," Patrick said. "For women with opioid dependency, we know that use of maintenance opioids like methadone decrease rates of preterm birth compared to heroin. For these women, neonatal abstinence syndrome may occur in their infants, but it is much better than the alternative, which is preterm birth."
The women prescribed painkillers were more likely to be white and to report having headaches or migraines and muscular or skeletal health problems. They were also more likely to have depression, to have an anxiety disorder and to smoke tobacco.
Forty-two percent of the women prescribed narcotics smoked during pregnancy, compared to 26 percent of the women not prescribed narcotics. The more cigarettes women smoked daily, the more likely she was to give birth to a baby with withdrawal.
"That's a modifiable behavior," Patrick said. "For women who are in maintenance treatment, dose didn't change the risk of neonatal abstinence syndrome, but smoking mattered a lot. So you can modify your infant's risk of drug withdrawal if you decrease the amount you smoke."
Taking selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant, with prescription narcotics also doubled the risk of newborn withdrawal, the study found.
"Infants with neonatal abstinence syndrome have longer, more complicated birth hospitalizations," Patrick said.
In this study, infants with neonatal abstinence syndrome were twice as likely as other newborns to be born with a low birth weight. They were also far more likely to have respiratory conditions, feeding difficulties and seizures.
"This is a really sobering article that shows the dangers of opioid prescription use during pregnancy," said Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City. "With this increase in prescription painkiller use, we're seeing an effect in our newborn population. If you think about how vulnerable our newborns are, this is really frightening."
Prescriptions for narcotic painkillers quadrupled between 2000 and 2009, and the number of babies born with neonatal abstinence syndrome during this time tripled, the authors said.
"Premature babies often have developmental delays and neurological problems, so anything you can do to reduce rates of prematurity, including avoiding opioids during pregnancy, you should," Wu said.
Neonatal abstinence syndrome may also have long-term effects that aren't clear.
"It's a constellation of symptoms," Wu said. "They might have seizures, which is frightening because you don't know if that's linked to a brain bleed or an infection, and you don't know what neurological outcome will come from those seizures."
The authors also calculated that each $1 spent on short-acting prescription narcotics correlated with $52 in hospital charges for newborn withdrawal.