A 27-Year-Old Pregnant Woman Was the Restrained Driver of a Vehicle

A 27-year-old pregnant woman was the restrained driver of a vehicle that hit the guardrail at a high rate of speed. She sustained a large laceration to the upper thigh and has lost a significant amount of blood. Vital signs are: heart rate 102, blood pressure 118/78 mmHg, respirations 18, and her skin is pale and clammy. Which of the following BEST explains this patient's presentation?

A) Maternal blood volume increases during pregnancy, allowing vital signs to remain normal despite significant blood loss.
B) Fetal oxygen demand increases after trauma, causing maternal blood pressure and heart rate to increase immediately after injury.
C) Maternal blood volume decreases during pregnancy, amplifying the effects of epinephrine and allowing for the maintenance of blood pressure.
D) Maternal vital signs remain normal following trauma to ensure the survival of the developing fetus.