Today's digital thermometers make taking a baby's temperature simple, with quick results. For best results in babies and toddlers up to 3 years of age, the American Academy of Pediatrics recommends taking the temperature rectally, by placing a thermometer in the baby's anus. This method is accurate and gives a quick reading of the baby's internal temperature. A newer method to measure temperature called temporal artery thermometry is also considered very accurate. It causes less discomfort than a rectal thermometer and is less disturbing to a newborn. It measures the temperature of the blood flowing through the temporal artery, on the forehead.
Taking the temperature under the arm (in the armpit) is called axillary measurement. It may be used to "screen" or get an idea about whether or not any child has a fever. If it shows a fever, the temperature should be rechecked by a more accurate method. Other types of thermometers, such as tympanic (ear) type thermometers, may not be accurate for newborns and require careful positioning to get a precise reading. Skin strips that are pressed on the skin to measure temperature are not recommended for babies. Touching a baby's skin can let you know if he or she is warm or cool, but you can't measure body temperature simply by touch.
Oral and rectal thermometers have different shapes and one should not be substituted for the other. Do not use oral thermometers rectally as these can cause injury. Rectal thermometers have a security bulb designed specifically for safely taking rectal temperatures.
Place the baby across your lap or changing table, on his or her abdomen, facing down. Place your hand nearest the baby's head on his or her lower back and separate the baby's buttocks with your thumb and forefinger.
Using your other hand, gently insert the lubricated bulb end of the thermometer one-half to one inch, or just past the anal sphincter muscle.
The thermometer should be pointed towards the child's belly button.
Hold the thermometer with one hand on the baby's buttocks so the thermometer will move with the baby. Use the other hand to comfort the baby and prevent moving.
Never leave a baby unattended with a rectal thermometer inserted.
Hold thermometer until it beeps or signals.
Remove the thermometer.
Wipe the bulb.
Read immediately and record.
Clean the thermometer with soap and water or rubbing alcohol.
Place the thermometer sensor in the middle of the baby's forehead.
Press and hold the scan button.
Slowly move the thermometer across the forehead toward the top of the baby's ear. Make sure it always touches the skin.
Stop at the hairline and release the scan button.
Remove the thermometer and read the temperature.
If a baby's rectal or temporal artery temperature is 100.4°F (38°C) or higher, call your baby's doctor.