Placing a pregnant patient in the supine position during the third trimester may...

• A. often cause hypotension secondary to cardiac compression.
• B. may decrease the amount of blood that returns to the heart.
• C. results in spontaneous urinary incontinence if the bladder is full.
• D. is recommended if the patient has severe abdominal discomfort.

Answer: (B)

In late pregnancy, lying on the back can cause supine hypotensive syndrome because the enlarged uterus can press on the inferior vena cava. This compression reduces venous return to the heart, which lowers preload and cardiac output, potentially causing maternal hypotension and dizziness.

The statement that best fits this scenario is that it may decrease the amount of blood that returns to the heart. That directly captures the mechanism: reduced venous return due to IVC compression when supine.

The other ideas aren’t the primary effect. The issue isn’t direct cardiac compression by the uterus, but venous compression causing less blood to return to the heart. Supine positioning is generally avoided in late pregnancy; turning to the left side is preferred to relieve the pressure. Urinary incontinence and using the position as a remedy for abdominal discomfort aren’t the central concerns here.