How does pregnancy affect the heart?

Pregnancy makes the heart and blood vessels work harder. During pregnancy, blood volume increases by 30% to 50% to nourish the growing baby. The heart also pumps more blood each minute, and the heart rate increases.

Labor and delivery add to the heart's workload too. During labor, there are sudden changes in blood flow and blood pressure, especially when pushing. After giving birth, stress put on the heart during pregnancy and labor slowly goes down over several weeks.