The number of pregnant women infected with Hepatitis C virus has nearly doubled over the past few years, according to the Centers for Disease Control and Prevention.

Dr. Stephen Patrick, a professor at Vanderbilt University School of Medicine, says, "From 2009 to 2014 the rate of hepatitis C infection among pregnant women almost doubled nationwide."

He thinks it is linked to the growing opioid epidemic. I-V drug use is the main risk factor for Hep C, which is now the country's most common blood-borne infection.

Hepatitis C is a contagious liver disease. It is caused by the Hep C virus and over time may result in serious liver damage.

In the U.S., it is estimated that about 3.5 million adults have chronic Hep C.

Since it does not exhibit symptoms during the early stages, many women are usually unaware that they have the virus.

There is no vaccine for Hepatitis C. The best way to prevent Hepatitis C is by avoiding behaviors that can spread the disease, especially injecting drugs.