The eruption of baby teeth begins when other changes in an infant’s immune system, growth, and development are also occurring. The eruption of the primary teeth usually begins around 6 months of age. This is, coincidentally, when infants have lost most of their maternally-derived antibody protection. By the age of 6 months, the number of maternal antibodies has decreased to a very low level, predisposing an infant to a variety of infections.

This means that if your baby has a fever it may not be due to teething.  You may need to take your baby to the pediatrician.