What is the main concern when placing a pillow under a pregnant woman’s hip?

Placing a pillow under a pregnant woman’s hip primarily aims to alleviate pressure from the abdominal artery, specifically the inferior vena cava. During pregnancy, lying on the back can compress this vein, which can impact blood flow returning to the heart and may lead to dizziness or decreased circulation. By raising the hip with a pillow, the vessel's compression is reduced, promoting better venous return and overall blood circulation for the mother and the developing fetus.

While comfort and back support are important considerations, the critical aspect in this context involves minimizing the risk of adverse effects associated with venous compression. Elevating the hips not only aids comfort but serves a significant physiological function in maintaining optimal blood flow during pregnancy.