As widespread injection drug use and opioid addiction continue to wreak havoc across the country, Midwestern states are starting to uncover a startling side effect of the crisis. According to a new report by the Centers for Disease Control (CDC), Wisconsin has seen a near doubling of women who test positive for hepatitis C virus (HCV) during pregnancy, which has in turn fueled a rise in the number of babies born with the virus, WebMD reports.

The study was released just as President Trump declared the opioid epidemic a public health emergency in his first major speech on the country’s opioid crisis late last week. By analyzing 2011 to 2015 data from Wisconsin’s Medicaid program, federal analysts discovered that the proportion of pregnant women with hepatitis C across the region increased 93 percent. They also found that the birth rate for HCV-positive mothers went up from 2.7 percent to more than 5 percent during this period.

Ultimately, this means far more babies are being exposed to hepatitis C while in the womb, which worries local doctors, since mother-to-child transmission of the virus occurs in about 6 percent of cases nationwide. Researchers also noted that across the state, only about one third of infants born to infected mothers were actually tested for HCV infection at birth, with the virus detected in nearly 4 percent of babies.

Study authors said they were particularly shocked by the low screening rate of infants born to women with hepatitis C in the study. Their recommendations: Test all pregnant women with hepatitis C risk factors, such as injection drug use or opioid addiction, and provide better monitoring of infants determined to be at risk for mother-to-child transmission.

The report also calls for educating women about the risk factors for contracting hepatitis C, additional testing among women of childbearing age and curing women who test positive for HCV with new direct-acting antiviral treatments before they get pregnant to help end such transmissions.

As in adults, signs of hepatitis C infection in infants often appear slowly and can take years to develop. However, some cases can be severe and require liver transplantation —a consequence of the crisis that hepatitis experts would rather avoid.