How much does cardiac output increase during pregnancy?

Cardiac output generally refers to the volume of blood pumped by the left or right ventricle per minute. During pregnancy, cardiac output typically increases by 30%–50%. The detailed explanation is as follows:

In pregnancy, cardiac output represents the total volume of blood pumped by the heart each minute and is one of the key indicators used to assess cardiac function. Due to physiological changes in the pregnant woman, cardiac output progressively increases. In healthy non-pregnant women, the normal cardiac output is usually around 4.5–5.5 L/min. During pregnancy, cardiac output rises gradually to meet the metabolic demands of both the developing fetus and the mother. Research indicates that cardiac output begins to increase in early pregnancy and reaches its peak in the late stages, typically increasing by approximately 30%–50% compared to pre-pregnancy levels. This increase is achieved through elevated heart rate and stroke volume. Heart rate refers to the number of times the heart beats per minute, which tends to rise during pregnancy. The increase in heart rate is modest in early pregnancy but becomes more pronounced in the third trimester. This is due to an expansion in circulating blood volume during late pregnancy, necessary to support both maternal and fetal needs.

In summary, cardiac output generally increases by 30%–50% above baseline levels. If a pregnant woman experiences tachycardia or other physical discomforts, prompt medical evaluation is recommended.