1. A 32-year-old primigravid woman comes to the physician at 30 weeks gestation because of a 10-day history of decreased appetite, intermittent nausea, and generalized itching. She has no history of serious illness, and her pregnancy has been otherwise uncomplicated. Her pulse is 98/mm and regular, and blood pressure is 104/64 mm Hg. Examination shows excoriations on the left shoulder. The lungs are clear to auscultation. A grade 2/6 systolic murmur is heard best at the left sternal border. The uterus is consistent in size with a 30-week gestation. Laboratory studies show: