"A rectal thermometer is best," says Paula Elbirt, M.D., author of Dr. Paula's House Calls to Your Newborn (Fisher Books, 2000). "It's accurate, easy to use, and reliable."
Remove a layer or two of your baby's clothing, and wait several minutes before taking his temperature. (Overdressing can nudge the gauge artificially higher, and even a few tenths of a degree can make a big difference in a newborn.) Apply petroleum jelly to the bottom half inch of the thermometer. Place your baby on his back. Then, holding both ankles with one hand, flex his knees against his belly so his legs resemble a frog's, and lift his bottom up. Gently stroke the area around the rectum with the thermometer, then insert it one half inch to one inch. Continue holding your little one's legs while holding the thermometer loosely so it can move along with your baby.
Call your doctor if his temperature is 100.4°F or higher.
All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.