A 25 year old nulliparous woman at 35 weeks' gestation comes to the labor and delivery ward complaining of contractions, a headache, and flashes of light in front of her eyes. Her pregnancy has been uncomplicated except for an episode of first trimester bleeding that completely resolved. She has no medical problems. Her temperature is 37 C (98.6 F), blood pressure is 160/110 mm Hg, pulse is 88/minute, and respirations are 12/minute. Examination shows that her cervix is 2 centimeters dilated and 75% effaced, and that she is contracting every 2 minutes. The fetal hea tracing is in the 140s and reactive. Urinalysis shows 3+ proteinuria. Laboratory values are as follows: leukocytes 9,400/mm3, hematocrit 35%, platelets 101,000/mm3. Aspaate aminotransferase (AST) is 200 U/L, and ALT 300 U/L. Which of the following is the most appropriate next step in management?