A woman in the third trimester of pregnancy is predisposed to hypotension while in the supine or sitting position due to the hemodynamic and anatomic changes of pregnancy. The large uterus of late pregnancy can compress the inferior vena cava (IVC) such that venous return is significantly reduced. This decreased preload can lead to decreased cardiac filling and hence decreased cardiac output and hypotension. This can be especially deleterious in the usual setting of increased cardiac demand in pregnancy.