Checking Your Baby's Body Temperature
Christine Sweeney, LICSW Program Manager, Parent Connection, BIDMC
OCTOBER 29, 2021
During the COVID-19 pandemic and as we enter cold and flu season, it is even more important to know how to get an accurate reading of your baby’s body temperature before your baby might be sick.
A fever is a sign that the body’s defenses are trying to fight an infection from viruses (such as a cold or the flu) or bacteria (such as strep throat or some ear infections), according to the American Academy of Pediatrics.
What is considered a fever?
A fever is typically 100.4 degrees Fahrenheit (38 degrees Celsius) or higher. However, please note that a “normal" temperature can vary with the child's age, activity, and time of day. Your child's temperature, age, and other symptoms will help your child’s medical provider recommend the best treatment.
When should I check my baby's temperature?
You know your child best, and checking your child’s temperature is a good idea if you or other caregivers notice a change in your child’s usual behavior, such as:
- Increased sleepiness or being less active than usual
- Increased irritability or more fussy than usual
- Your child isn't hungry or eating as well as usual
- Your child’s body feels warmer or cooler than usual
- Your child’s color is rosy or flushed, or very pale or mottled (looks like marble)
What should I use to take my baby's temperature?
Use a basic digital thermometer. Most can be used rectally, orally, or under the arm and purchased for under $10.00. Glass or mercury thermometers should never be used and should be disposed of properly.
What method should I use to take my baby's temperature?
- From newborn up to three months, the American Academy of Pediatrics recommends taking rectal temperatures.
- For three months to three years, it’s still fine to take the temperature rectally, axillary (under the arm), or in the ear (this requires a special thermometer).
How do I take my baby's temperature?
Taking a rectal temperature:
- Clean the end of the thermometer with rubbing alcohol, or soap and water. Rinse in lukewarm water and dry.
- Apply a small amount of lubricant, such as petroleum jelly, on the end of the thermometer that will enter the rectum.
- Place the baby, tummy down, across your lap. Hold the baby by placing your palm against their lower back, or place the child face-up and bend their legs to their chest. Rest your free hand against the back of their thighs.
- With your other hand, turn the thermometer on and insert it one half to one inch into the anal opening (be sure not to insert it too far). Hold the thermometer in place loosely with two fingers, keeping your hand cupped around the baby's bottom. When you hear the thermometer beep, remove it and check the reading.
- Re-clean the thermometer.
- Label the thermometer, so it is not accidentally used in the mouth.
Taking an axillary (under the armpit) temperature:
- Turn on the thermometer and place the small end in your baby's armpit. Make sure it is touching only skin, not clothing.
- Gently hold your baby's arm in place until the thermometer beeps.
Notify your baby's medical care provider of a rectal temperature over 100 degrees Fahrenheit, an axillary temperature more than 99.6 degrees Fahrenheit, or a low temperature below 97 degrees Fahrenheit.