Which physiological change occurs in the cardiovascular system during pregnancy?

During pregnancy, one of the significant physiological changes in the cardiovascular system is an increased pulse rate. This increase occurs as the body works harder to supply oxygen and nutrients to the growing fetus and to accommodate the increased blood volume that typically rises significantly during pregnancy.

As the pregnancy progresses, the heart must pump more blood to support both maternal and fetal needs, leading to an elevated pulse rate, which helps meet the metabolic demands of the mother and the developing fetus. This adjustment is crucial for maintaining adequate circulation and ensuring that both the mother and fetus receive sufficient oxygen and nutrients.

In contrast, other options relate to cardiovascular changes but do not accurately reflect the adaptations noticed during pregnancy. For instance, blood volume does increase significantly, contributing to a rise in cardiac output rather than a decrease. Moreover, heart output typically increases, not decreases, throughout pregnancy to accommodate the increased demands. Blood pressure can vary, but it generally may decrease in early pregnancy due to hormonal changes that promote vasodilation, not an overall decrease across the entire pregnancy term.