What effect does pregnancy typically have on heart rate (HR)?

During pregnancy, a woman's body undergoes several physiological changes to support the developing fetus, one of which includes an increase in blood volume and cardiac output. This natural physiological response to accommodate both maternal and fetal needs generally leads to an increase in heart rate by about 10 to 15 beats per minute.

The elevation in heart rate assists in ensuring that adequate oxygen and nutrients are delivered to the baby while also helping to remove waste products efficiently. Additionally, the increase in metabolic demand during pregnancy -- due to factors such as increased workload on the heart and changes in hormone levels -- further contributes to this rise in heart rate.

This explanation highlights the body's adaptations during pregnancy, demonstrating why a slight increase in heart rate is expected rather than a decrease or unchanged rate, which would not adequately support the increased demands of both the mother and the developing fetus. Understanding this physiological change is crucial for recognizing how the cardiovascular system functions during pregnancy and providing appropriate care for expectant mothers.