One of the biggest concerns for new parents is to know when your baby is sick. Measure the temperature is one of the first things we do to make sure if it is right or wrong. But once we take the temperature we have to know how to interpret the results, and we should not treat it like temperature of an adult.
Even 37,5º we should worry, there is within normal.
From 37.5 ° to 38 ° is considered as fever.
From 38th is considered as fever and high fever above 39 °, but we need not associate with greater severity.