What acid-base disturbance is commonly seen in pregnant women?

Pregnant women often experience respiratory alkalosis due to physiological changes that occur during pregnancy. As the uterus expands, it can press against the diaphragm, leading many pregnant individuals to adopt a more upright posture for comfort. This change, combined with the increased minute ventilation caused by rising progesterone levels, results in enhanced respiratory drive and increased tidal volume. Consequently, women tend to hyperventilate, leading to an increased exhalation of carbon dioxide (CO2) and a decrease in arterial CO2 levels.

The reduced CO2 levels in the blood elevate the pH, creating a state of respiratory alkalosis. This condition is typically well-tolerated and is a normal physiological adaptation to ensure adequate oxygen delivery to both the mother and the developing fetus. Understanding this physiological adaptation is important for managing the care of pregnant patients, as recognizing respiratory alkalosis helps differentiate it from other acid-base disturbances that may arise due to underlying pathology.