The key to taking a baby's temperature under the arm is to keep the arm close to the baby's body throughout the entire process. Doctors do not recommend obtaining a baby's temperature under the arm for infants less than 3 months old due to the possibility of inaccurate readings.
- Find the appropriate thermometer
Get the right thermometer for the job. Use an oral thermometer for an armpit reading, preferably a digital model.
- Activate the thermometer
Turn on the digital thermometer, and follow the device's instructions. This means holding the thermometer under your baby's arm for a few minutes until it beeps.
- Keep the bulb against the skin
You must keep the bulb of the thermometer against your baby's skin during the entire time the device takes a reading. Hold your baby on your lap, and keep the infant's arm crossed against his chest to ensure the armpit remains closed as much as possible. You can also hold your baby's arm against the side, or try leaning your baby against your body. Distract your infant with food or a toy if the youngster fidgets.
- Read the thermometer
The digital thermometer is done when it beeps. Look at the temperature reading, which may be as much as 2 degrees Fahrenheit lower than an internal rectal temperature.