Why is the supine position generally avoided in late-pregnancy patients?

Why is the supine position generally avoided in late-pregnancy patients?

• A. Compresses the aorta and vena cava
• B. Improves venous return
• C. Has no effect on blood flow
• D. Reduces uteroplacental blood flow

Answer: (A)

In late pregnancy, lying on the back allows the enlarged uterus to press on the major vessels, especially the inferior vena cava and the abdominal aorta. This compression reduces venous return to the heart (lowering preload and cardiac output) and decreases blood flow through the aorta to the placenta, leading to reduced uteroplacental perfusion. The result is maternal hypotension and potential fetal hypoxia or distress. That’s why this position is avoided. An alternative, like the left lateral position, relieves this pressure and improves both maternal circulation and placental blood flow.

In late pregnancy, lying on the back allows the enlarged uterus to press on the major vessels, especially the inferior vena cava and the abdominal aorta. This compression reduces venous return to the heart (lowering preload and cardiac output) and decreases blood flow through the aorta to the placenta, leading to reduced uteroplacental perfusion. The result is maternal hypotension and potential fetal hypoxia or distress. That’s why this position is avoided. An alternative, like the left lateral position, relieves this pressure and improves both maternal circulation and placental blood flow.