Which physiological change commonly occurs during normal pregnancy to improve oxygen delivery to the fetus?

During normal pregnancy, increased cardiac output is a key physiological change that enhances oxygen delivery to the fetus. As the body adapts to meet the increased metabolic demands of both the mother and the developing fetus, cardiac output rises significantly. This increase is achieved through several mechanisms, including an increase in blood volume and changes in heart rate, which combine to promote efficient blood flow to the placenta where oxygen transfer occurs.

Increased cardiac output facilitates the delivery of oxygen-rich blood to the uteroplacental circulation, ensuring that the fetus receives adequate oxygen for growth and development. This adaptation helps to meet the demands of a growing fetus, especially in the later stages of pregnancy when these demands are more pronounced.

Other options, while relevant to the context of pregnancy, do not directly align with the primary physiological change aimed at improving oxygen delivery. Increased hematocrit would generally indicate a higher proportion of red blood cells in the blood, which can occur for various reasons and may not improve oxygen delivery if overall blood volume is also increased. An increase in PaO2 may not be significant since, during pregnancy, the maternal blood gas levels can be influenced by respiratory changes. Maternal hyperventilation leads to a state of respiratory alkalosis that may not directly correlate with improved fetal oxygen