There is a lot of talk about avoiding hot baths and hot tubs when trying to conceive. High heat for a prolonged period of time may cause some fetal malformations such as neural tube defects.
We are, however, not sure how this happens or what the cut off should be in terms of temperature or duration. Occasional Tylenol® is probably safe and helpful if you develop a fever. Drinking more fluids or drinking ice water will be helpful in reducing your temperature.