Is it safe early in pregnancy?

The active ingredient of Robitussin is guaifenesin. According to the Medline web site, "... several groups of women taking guaifenesin during pregnancy have been studied. In one group, when guaifenesin was taken during the first 3 months of pregnancy, the babies had more inguinal hernias than expected. However, more birth defects than expected did not occur in the babies of other groups of women taking guaifenesin during pregnancy. Studies have not been done in animals."