Final answer:
Pregnant women see an increase in cardiac output due to the increased maternal blood volume and the body's need to manage fetal nourishment and waste removal. Hormonal changes and the increased metabolic rate also contribute to the need for a higher CO.
Step-by-step explanation:
During pregnancy, cardiac output (CO), which is the amount of blood the heart pumps per minute, increases significantly. This is primarily to accommodate the increased maternal blood volume by approximately 30 percent, which is necessary for supporting the physiological needs of both the mother and the fetus. This rise in blood volume and CO helps to manage the requirements of fetal nourishment and waste removal effectively.
Several factors contribute to the increase in CO during pregnancy:
- The anterior pituitary gland enlarges and boosts the production of hormones such as thyrotropin, which increases the production of thyroid hormone, thus raising the maternal metabolic rate.
- Increased metabolic rate requires more oxygen and nutrients, which are delivered through the bloodstream, hence a higher CO is needed to meet these demands.
- Parathyroid hormone levels also rise to mobilize calcium from the mother's bones for fetal use, all of which requires an efficient circulatory system.
Moreover, the pulse and blood pressure moderately increase during pregnancy as a result of the increased blood volume. The growing uterus places pressure on the pelvic blood vessels, affecting the venous return and contributing to changes in the circulatory system. It is essential for pregnant women to have regular check-ups to monitor their cardiovascular health during pregnancy.