Many pediatricians consider a rectal thermometer the “gold standard” for taking a baby’s temperature when you suspect a fever, and suggest measuring it that way. (The American Academy of Pediatrics considers rectal readings to be the most precise way to take a temperature for infants and children under age 3.)

If you're not comfortable with the idea, you’re not alone. Taking a temperature rectally gets easier with practice. And most babies don’t mind it as much as you’d think. Here are some suggestions:

* Clean the end of a digital rectal thermometer with soap and water or rubbing alcohol (whatever the instructions direct). Rinse it with cool water; don’t use hot.

* Apply the probe cover, if you are using one, and put a dab of petroleum jelly on the end of the cover, or on the thermometer if you are not using a cover.

* Place your baby tummy-down on your lap or a firm surface, such as a changing table or bed (always make sure you have a hand on the baby). Hold him with your hand on his lower back. With your other hand, turn on the thermometer and insert it 1/2 to 1 inch (or to the length indicated on the thermometer) into your baby’s bottom.

* Wait until you hear the thermometer beep or until the required amount of time has passed, anywhere from 5 to 90 seconds (it varies per thermometer). Remove the thermometer and check the reading.

* Write the temperature down in case your pediatrician or the nurse asks for it.

* Don’t hesitate to call the pediatrician when your baby has a fever (over 100.4 degrees F), or if you’re worried.

See our blog post on ibuprofen better than acetaminophen for children's fevers? , as well as our reports on thermometers, taking baby's temperature, and what's a normal temperature for a baby? for more information.