What physiological change occurs in pregnancy related to blood volume?

During pregnancy, there is a significant physiological change in blood volume, characterized by an increase. Blood volume expands to support the growing fetus and to accommodate the increased demands of the maternal body. This increase can be as much as 30-50% (or 1 to 1.5 liters) by the third trimester. The expansion of blood volume plays a critical role in ensuring adequate uteroplacental perfusion and facilitating nutrient and oxygen transport to the developing fetus.

In addition, this increased blood volume helps regulate blood pressure and prevents the mother from entering a state of hypovolemia as she experiences changes like increased metabolic demands and the need for enhanced circulation. Overall, the increase in blood volume is a vital adaptation during pregnancy that supports both maternal and fetal health.