A 28-year-old woman in the third trimester of pregnancy has experienced severe dizziness for several days and is admitted to the hospital. During physical examination her blood pressure is normal when standing or sitting. When the patient is supine, her blood pressure drops to 90/50 mm Hg. What is the most likely explanation for these findings?
The inferior vena cava quite likely undergoes compression by the growing fetus when the mother is in the supine position. In this case the compression led to reduced blood flow through the heart, with a resultant drop in blood pressure. The other structures listed as answers are not likely to be compressed by the growing fetus.
Compression of the inferior vena cava
Compression of the superior vena cava
Compression of the aorta
Compression of the common carotid artery
Thorax