SOUTH BEND, Ind. (AP) — The Indiana Department of Health says it’s working to collect data on a withdrawal syndrome in newborns amid the country’s opioid abuse epidemic.

Neonatal abstinence syndrome occurs when the transfer of harmful substances from mother to baby abruptly stops at the time of birth.

The South Bend Tribune reports that while the syndrome can be caused by several substances, it’s most commonly the result of opioids.

The department tested babies at 27 hospitals this year. The agency found about 16 percent of newborns tested at the participating hospitals had been exposed to opioids while in the womb.

Health Department official Martha Allen says she suspects the problem is worse because not every baby at the hospitals is tested.