Which of the following statements about physiological changes in the cardiac system during pregnancy is NOT TRUE?

The statement regarding a progressive increase in heart rate throughout pregnancy is not true. During pregnancy, the body undergoes numerous physiological changes to accommodate the growing fetus and support the mother's health. While cardiac output does increase due to an increase in blood volume and stroke volume, the heart rate does not steadily rise throughout the entire pregnancy.

Typically, heart rate may slightly increase during the first trimester and stabilize or show less of a significant increase as pregnancy progresses towards the third trimester. It’s essential to understand that the increase in blood volume and decreased peripheral vascular resistance causes the blood flow to be more efficient, and cardiac output rises mainly because of stroke volume, not just heart rate.

This understanding of the physiological changes helps midwives monitor expected maternal adaptations and identify when variations may indicate complications.