The nurse is caring for a 60-year-old female client scheduled for abdominal surgery. Which factor in the client's history indicates that the client is at an increased risk for deep vein thrombosis (DVT) in the postoperative period?
A. Past hypersensitivity to heparin
B. Family history of uterine cancer
C. Estrogen replacement therapy for the past three years
D. History of acute hepatitis A.