<prompt> 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 9050 mm Hg. What is the most likely explanation for these findings?Compression of the inferior vena cavaCompression of the superior vena cavaCompression of the aortaCompression of the common carotid artery  <response>: 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. 