Final answer:
Pregnant patients are more sensitive to anesthetics due to hormonal changes, particularly increased estrogen, which heightens nerve sensitivity, as well as physiological adjustments such as increased blood volume and altered immune response.
Step-by-step explanation:
Pregnant patients are more sensitive to epidural/intrathecal anesthetics primarily due to hormonal changes that occur during pregnancy. These changes include a marked increase in the production of estrogen which can lead to an increase in nerve fiber sensitivity, making the central nervous system more reactive to anesthetic agents. Additionally, pregnant women experience substantial physiological changes, such as an increased blood volume by up to 30 to 50 percent. This heightened blood volume can cause anesthetics to be distributed differently throughout the body's tissues, contributing to increased sensitivity. Another key change is the downregulation of the immune system to prevent the rejection of the fetus, which can alter the body's response to various medications, including anesthetics.