Wererats in Utero by Terry Miller

Raven, Ian, and Brad wake up inside a mysterious facility. Ian and Brad are kept in separate cells made of inpenetrable glass. Raven, however, finds herself strapped to a hospital bed in a dark lab, a guinea pig for Mr. Bowling, a strange, pale man in a trenchcoat, and his employed staff. She's not the only pregnant wererat in the facility, though, as Mr. Bowling seeks to create hybrids for an army to tip the scales in his, and his kind's, favor in a war with the plethora of supernatural creatures stalking the night.