During pregnancy, the heart pumps 30% to 50% more blood than usual each minute to nourish your growing baby. Pregnancy causes an increase in heart rate, as well as stress to your heart and circulatory system. During labor and delivery, your body endures sudden changes in blood flow and pressure. It might take several weeks after delivery for your heart to return to its pre-pregnancy levels. Pregnant women with health complications such as high blood pressure and gestational diabetes face a higher risk of cardiovascular disease later in life.