Why should a pregnant woman avoid using a hot tub during pregnancy according to the nurse's recommendation?

A pregnant woman is advised to avoid using a hot tub primarily because it may cause overheating. When a woman immerses herself in hot water, especially at high temperatures maintained in hot tubs, her body temperature can rise significantly. Elevated maternal body temperature, especially in the first trimester, is associated with potential risks to fetal development, including neural tube defects and other complications.

Maintaining a normal body temperature is crucial during pregnancy, as the developing fetus is sensitive to extremes in temperature. The risk of overheating is a key concern because it can affect the fetus's health, potentially leading to adverse outcomes. While other considerations such as dehydration and fetal tachycardia can be relevant, the primary issue with hot tub use is centered around the risks associated with increased body temperature.