1. How to judge whether the baby has a fever? 1.1 How to use a thermometer 1.2 Definition and standards of fever Baby fever is a matter of great concern to parents, but how to judge whether the baby has fever? First of all, we need to learn to use the thermometer correctly. Place the thermometer under the baby\’s armpit or anus, and the measured temperature is the body temperature. Secondly, we need to understand the definition and standards of fever. Normal human body temperature fluctuates between 36°C and 37°C. When it exceeds 37.5°C, it is mild fever, when it exceeds 38°C, it is moderate fever, and when it exceeds 39°C, it is high fever.