During pregnancy, alterations occur in nearly every maternal organ system, with associated implications for anesthesiologists (Table 40-1: Physiologic Changes of Pregnancy) (Braveman FR, Scavone BM, Blessing M, Wong CA. Obstetrical anesthesia. In: Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Ortega R, Stock MC, eds. Clinical Anesthesia. Philadelphia: Lippincott Williams & Wilkins; 2013:1144–1177).