The fast-growing abuse of prescription drugs has reached maternity wards in hospitals across the country, with the number of pregnant women addicted to opiate drugs — and the number of babies born experiencing withdrawal symptoms — rising sharply over the last decade.

A new study in The Journal of the American Medical Association has quantified the growth of the problem for the first time, as well as the increase in the costs of treating these newborns.

The study estimated that every hour a baby is born in the United States with symptoms of withdrawal from opiates — roughly 13,500 babies a year. The condition, known as neonatal abstinence syndrome, can cause seizures, breathing problems, dehydration, difficulty feeding, tremors and irritability. Many infants are hospitalized for several weeks while doctors treat them with methadone or morphine to gradually wean them from their dependence on the drugs that their mothers used.

“The incidence has gone crazy and I think it has the potential to become a national or international issue,” said Marie J. Hayes, a clinical neuroscientist at the University of Maine, and an author of an editorial accompanying the study. “People who previously might not have used heroin or the needle are more likely to use prescription opiates.”