Those babies are born earlier than average and with a higher risk of breathing problems and seizures, and they require careful monitoring and treatment to wean them off the drugs before they can go home.

Researchers also found that the number of new moms who tested positive for use of opiates -- which include powerful painkillers such as oxycontin -- increased five-fold between 2000 and 2009. In the most recent study year, between five and six out of every 1,000 women had the drugs in their system.

"This study is part of a bigger call to the fact that opiates are becoming a big problem in this country," said Dr. Stephen Patrick from the University of Michigan in Ann Arbor, who worked on the study.

Recent research has shown the number of people who both abuse opiates and who overdose has been increasing in the U.S. According to the Centers for Disease Control and Prevention, 14,800 people died of a prescription drug overdose in 2008 -- triple the estimate from 20 years earlier.

It's unclear if there are long-term health impacts for kids who are born to opiate-addicted moms and get through their first weeks of life okay. Some but not all studies on the question have found those kids grow up with a higher risk of developmental problems, according to Patrick.

What is clear is that babies born in opiate withdrawal significantly drive up health care costs, especially for state Medicaid programs.

According to the new analysis, the average hospital stay for a newborn in withdrawal topped $50,000 in 2009 -- with about 80 percent of that being paid by the government-funded insurance program for the poor.

That's in part because those babies were kept in the hospital for an average of 16 days after being born -- compared to just three days for other newborns, which cost an average of less than $10,000 to deliver.

The data come from discharge records for kids treated at more than 4,000 hospitals nationwide and statistically adjusted to represent the entire U.S. population.

Those records, which include all diagnoses made before a baby was sent home, showed that the number of infants born with symptoms of opiate withdrawal increased from one in 1,000 in the year 2000 to more than three in 1,000 in 2009.

That works out to about 13,500 newborns born in the U.S. in 2009 in withdrawal, the researchers reported in the Journal of the American Medical Association.

The study was published online Monday to coincide with a presentation at the Pediatric Academic Societies Annual Meeting in Boston.

It's not usually difficult to spot a baby that is in opiate withdrawal, Patrick told Reuters Health. Those infants "are far more inconsolable than other babies," he said. "They appear uncomfortable, sometimes they breathe a little faster... they're scratching their faces."

"A CRISIS CONDITION"

Marie Hayes, from the University of Maine in Orono, said the increasing abuse of prescription opiate medications -- and babies being born in opiate withdrawal -- is mainly centered in a few pockets of the U.S., including in rural Kentucky, Tennessee and Maine. Parts of Florida are also becoming known as hubs of opiate abuse.

"The concern is that it will be more widespread," Hayes, who wrote a commentary published with the new study, told Reuters Health.

She said in her experience, a few babies who are born in opiate withdrawal have mothers that needed to be on strong painkillers after they were in a car accident, for example. And a very small number have moms who are addicted to heroin.

But about 85 percent of the cases she sees are a result of women who abuse prescription drugs.

"This has become a crisis condition in neonatology," Hayes said.

One of the concerns is that there aren't enough methadone clinics for pregnant women who are addicted to painkillers and are also often suffering from depression and anxiety. Strategies that involve giving safer substitute drugs to addicted women, but no counseling or extra support, typically don't work that well, she added.

And stopping opiate use abruptly can also be dangerous for moms and babies, Patrick said.

The researchers agreed there's a need for more research on how best to care for drug-addicted women and babies who are born in withdrawal -- as well as an urgency to spread the message about the dangers of opiate use in pregnancy.

"We need to put the light on this problem, and get it out there as a public health crisis," Hayes said.

SOURCE: bit.ly/4HWZ7 Journal of the American Medical Association, online April 30, 2012.

• A Permanent Economic Emergency