How does pregnancy primarily affect the respiratory system?

During pregnancy, significant physiological changes occur, particularly in the respiratory system, in response to the demands of both the mother and the developing fetus. One of the key changes is the increase in tidal volume, which is the amount of air inhaled or exhaled with each breath. This increase helps to accommodate the elevated oxygen requirements during pregnancy, ensuring that both the mother and the fetus receive adequate oxygen supply.

At the same time, there is a decrease in functional residual capacity (FRC), which is the volume of air remaining in the lungs after a normal exhalation. This reduction is primarily due to the upward displacement of the diaphragm caused by the growing uterus. The decrease in FRC means that there is less air left in the lungs after expiration, which impacts the overall lung function but allows for more efficient gas exchange during inhalation due to the increased tidal volume.

The combination of increased tidal volume and decreased functional residual capacity illustrates the body's adaptation to the increased metabolic demands of pregnancy, reflecting the need for greater oxygen intake and carbon dioxide expulsion. Hence, this choice accurately captures the primary respiratory adaptational responses that occur during pregnancy.