A 35-Year-Old Woman, Gravida 1 Para 0, at 27 Weeks

A 35-year-old woman, gravida 1 para 0, at 27 weeks gestation is evaluated in the labor and delivery unit after she was involved in a motor vehicle collision.  The patient was initially evaluated in the emergency department and then was transferred to labor and delivery in stable condition after repair of a facial laceration.  She was restrained by a lap-and-shoulder belt; the airbag was deployed.  In addition to the facial laceration, the patient has dull abdominal pain.  She reports no vaginal bleeding or leakage of fluid and has had multiple fetal movements since the collision.  The patient was previously evaluated in the emergency department at 9 weeks gestation for persistent nausea, and an ultrasound at that time confirmed gestational age.  She has otherwise had no prenatal care.  The patient has no chronic medical conditions or prior surgeries.  She does not use tobacco, alcohol, or illicit drugs.  Blood pressure is 100/70 mm Hg, pulse is 104/min, and respirations are 16/min.  Pulse oximetry is 99% on room air.  The abdomen is mildly tender at the uterine fundus, without rebound or guarding.  Sterile speculum examination confirms a closed cervix and no vaginal bleeding or rupture of membranes.  The fetal heart rate tracing has a baseline of 130/min with moderate variability, accelerations, and no decelerations.  The tocometer exhibits low-amplitude contractions every 3 minutes.  Initial laboratory results are as follows: Which of the following is the best next step in management of this patient?

A) Administer corticosteroids and initiate induction of labor
B) Initiate magnesium and tocolytic therapy
C) Order a Kleihauer-Betke test and continue fetal monitoring
D) Perform a bedside biophysical profile
E) Transfuse 2 units of packed red blood cells