Which blood vessel can be compressed in a heavily pregnant woman if resuscitation is attempted while she is lying on her back?

In a heavily pregnant woman, the weight of the uterus can compress the inferior vena cava when she is lying on her back. This large vein carries deoxygenated blood from the lower body to the heart. If the inferior vena cava becomes compressed, it can lead to reduced blood flow to the heart, potentially causing hypotension and restricting blood circulation to vital organs. This scenario is particularly relevant during resuscitation efforts, where maintaining adequate blood flow is critical for effective outcomes.

The aorta, although it plays a crucial role in blood circulation, is positioned higher in the body, and its compression is less likely to occur from the weight of the uterus. The coronary arteries supply blood to the heart muscle itself, and while they are vital for heart function, they are not typically affected by the mechanical pressure exerted by a gravid uterus. Similarly, the pulmonary veins, which return oxygenated blood from the lungs to the heart, are located in a way that makes them less susceptible to compression from the weight of the uterus.