What alteration in heart rate occurs during pregnancy?

During pregnancy, an increase in heart rate is a physiological adaptation that supports the growing demands of both the mother and the developing fetus. As blood volume increases to accommodate the needs of the fetus and the demand for nutrients and oxygen, the heart works harder and pumps more blood per minute, resulting in a rise in heart rate. Typically, a woman's resting heart rate may increase by about 10 to 20 beats per minute during the course of a normal pregnancy.

This response to pregnancy is crucial for maintaining adequate blood flow, supporting the expanding circulatory system, and ensuring that the metabolic needs of both the mother and the fetus are met. The increased heart rate, often referred to as tachycardia, is a normal occurrence and is part of the body's adaptations to support the changes that pregnancy entails. This increased demand can also be attributed to factors such as hormonal changes and increased physical activity often associated with pregnancy.