Why is it dangerous to get my temperature up?

Plan ahead for heat. Women living in hot climates should take steps to avoid going out in the heat without being able to get cool. Also many studies show complications from using hot tubs due to unexpected overheating. Early in the pregnancy or prior to a temperature change (eg, vacation) women should ask OB providers for rules about what to do in extreme temperatures, especially if in them for extended periods.
Baby temp is higher. If a woman is pregnant, there are risks from elevated temperature. One reason is that the temperature of the fetus runs higher than that of the mother, and that places demands on the heart. Another is that the elevated temperature might indicate an infection, which can cause problems for both mom and baby. So if pregnant, a woman should ask a physician at what temperature she should call if ill.