Your Baby (An owner’s manual)

Taking Your Baby’s Temperature

The most accurate way to take your baby’s temperature is rectally. To do so, you’ll need a digital rectal thermometer. Old-style mercury thermometers should not be used because of the potential exposure to mercury, which is toxic.

  • To start, clean the end of the thermometer with rubbing alcohol or soap and water. Rinse it with cool water. Do not rinse with hot water.
  • Put a small amount of lubricant, such as petroleum jelly, on the end of the thermometer.
  • Place your child’s belly down across your lap or on a firm surface, such as a changing table. Hold him by placing your palm against his lower back, just above his bottom.
  • With the other hand, turn on the thermometer switch and gently slide the probe end of the thermometer 1⁄2 to 1 inch into the anal opening. Stop inserting the thermometer if it becomes difficult to insert. Never force the thermometer into the rectum.
  • Hold the thermometer in place loosely with two fingers, keeping your hand cupped around your child’s bottom. Never force the thermometer or insert it too far.
  • Hold in place for about one minute, until the thermometer beeps. Remove the thermometer and check the reading.
  • Afterward, be sure to clean the thermometer in hot, soapy water.

Our Baby Tech Experts:

Ari Brown, M.D., coauthor of Baby 411: Clear Answers & Smart Advice for Your Baby’s First Year (Windsor Peak Press, 2005) Jennifer Shu, M.D., coauthor of Heading Home with Your Newborn (American Academy of Pediatrics, 2005) Stacy Whitman, a freelance writer based in Sun Valley, Idaho, can now change a diaper with one hand and can’t remember the last time she cried.