A nurse is educating a group of clients about the contraindications of warfarin therapy. Which of the following statements should the nurse include in the teaching?

A. "Clients who have glaucoma should not take warfarin." Glaucoma is not a contraindication for warfarin. Warfarin affects clotting factors, not intraocular pressure. B. "Clients who are pregnant should not take warfarin." Warfarin (Coumadin) is a teratogen (Pregnancy Category X). It crosses the placenta and can cause fetal hemorrhage, spontaneous abortion, and severe congenital defects (fetal warfarin syndrome). Pregnant clients requiring anticoagulation are typically switched to Heparin or Enoxaparin (Lovenox), which do not cross the placenta. C. "Clients who have hyperthyroidism should not take warfarin." While hyperthyroidism can increase the metabolism of clotting factors (potentially increasing the INR response), it is not a contraindication. The dose just needs to be monitored and adjusted closely. D. "Clients who have rheumatoid arthritis should not take warfarin." Rheumatoid arthritis itself is not a contraindication. However, the nurse should warn the client about interacting medications often used for RA (like NSAIDs), which increase bleeding risk.