During pregnancy, how does the minimum alveolar concentration (MAC) change?

The minimum alveolar concentration (MAC) is a measure of the potency of anesthetic agents and reflects the concentration required to prevent movement in response to a surgical stimulus in 50% of patients. During pregnancy, hormonal and physiological changes can significantly affect the body's response to anesthetics.

As pregnancy progresses, there is an increase in progesterone levels, which can enhance the effect of anesthetics, leading to a decreased MAC. Additionally, the increased blood volume and alterations in physiological parameters, such as respiratory function and metabolism, can further contribute to this decrease. It is observed that the MAC generally continues to decrease throughout the entirety of the pregnancy, reflecting these changes, making it necessary for anesthesiologists to adjust dosages accordingly to ensure the safety and efficacy of anesthesia during this period.

Thus, the correct answer indicates that there is a consistent reduction in MAC, highlighting the physiological adaptations that occur during pregnancy that affect anesthetic requirements.