Pregnancy causes notable hematologic changes, including physiological anemia and a heightened risk of clot formation, known as a hypercoagulable state. Physiological anemia occurs because the plasma volume increases more than the red blood cell mass, leading to a dilution effect. Although this improves placental circulation by reducing blood viscosity, it results in lower hemoglobin and hematocrit levels than in non-pregnant individuals. While generally well tolerated, these changes must be considered during anesthesia, especially in cases where significant blood loss, such as in cesarean sections, may occur. Anesthesia providers must closely monitor hemoglobin levels and ensure adequate oxygenation to support both mother and fetus.
The hypercoagulable state during pregnancy prepares the body to prevent excessive bleeding during delivery. However, this increased clotting tendency also heightens the risk of thromboembolic events during pregnancy and postpartum. This is a critical factor when considering regional anesthesia, such as epidurals and spinal blocks, due to the risk of epidural hematoma, a rare but serious complication. While routine platelet counts may not be required for healthy pregnant women, they are crucial for those with conditions like preeclampsia, where platelet counts may drop significantly. In high-risk cases, advanced testing like thromboelastography can offer a clearer picture of the patient's coagulation status before regional anesthesia is administered.
