It's natural for parents to be concerned if they notice a mild fever in their infant. A slightly high temperature is not typically a problem in babies over three months of age but merely a sign that the infant is fighting off a minor infection.
Definition
In babies, a fever is defined as any temperature over 99.5 degrees Fahrenheit, or 37.5 degrees Celcius, taken with an oral thermometer. If using a rectal thermometer, these numbers are slightly higher and anything under 100.4 degrees Fahrenheit or 38 degrees Celcius is not considered a fever. A mild fever is typically considered anything within fever range but under 103 degrees Fahrenheit.
Rectal Temperature
Rectal thermometers provide the most accurate gauge of an infant's temperature, but oral thermometers may also be used on infants over three months of age. To take an infant's temperature rectally, the baby should be placed face down on an adult's lap or flat surface and a lubricated digital rectal thermometer inserted about 1/2 inch into the rectum. The thermometer should be removed when it beeps to indicate the reading is complete and the caregiver can then read the temperature from the display window.
Oral Temperature
To take a baby's temperature orally, an oral digital thermometer can be placed under the tongue and the child instructed to hold it there until the thermometer beeps to signal that it is ready to be removed and read. Digital pacifier thermometers are also available that can be used by a baby too young to understand how to hold an oral thermometer in his mouth.
Treatment
For babies over three months, treatment is not generally required for a mild fever under 100.2 degrees Fahrenheit when taken orally. Because fever indicates that the infant's body is fighting off an infection, it is generally a good idea not to give any medications that might interfere with this process. However, if the infant is fussy or otherwise seems to be suffering from other issues in addition to the fever, such as a runny nose, parents can consult a doctor for advice on safe medicines to give their baby. Babies under three months of age should be brought to a doctor or hospital for any fever, even a mild one. Babies with a mild fever should be encouraged to sleep and should be given lots of liquid, preferably in the form of breast milk or formula. Breast milk contains antibodies that help fight off disease, so breastfeeding mothers should continue to provide breast milk throughout a baby's illness.
Concerns
Infants under three months can develop serious illnesses extremely rapidly, so it is vital to contact a doctor for any degree of fever, even a mild case. Babies who are three to six months need a doctor's care if their fever rises above 101 degrees Fahrenheit, even when they appear fine. Infants over 6 months old should see a doctor if they develop a fever over 103 degrees Fahrenheit or if they have a fever over 102 degrees Fahrenheit more than two days or are acting irritable or uncomfortable.
