Which position should pregnant women not lie in due to vena cava compression?

• A. Supine
• B. Left lateral
• C. Prone
• D. Sitting up

Answer: (A)

In late-pregnancy, lying flat on the back can press the uterus against the inferior vena cava. That compression reduces venous return to the heart, lowers preload and cardiac output, and can decrease placental blood flow, risking maternal hypotension and fetal distress. The best position to prevent this is to lie on the left side (left lateral decubitus); it shifts the uterus off the vena cava, improves venous return, stabilizes blood pressure, and enhances uteroplacental perfusion. Prone is not suitable because it presses on the abdomen, while sitting up offers only partial relief and is not as effective as left-side positioning. Therefore, supine should be avoided in late pregnancy.