A rectal temperature is taken by placing a thermometer in your baby’s bottom. This method provides the most accurate reading. Talk with your baby's healthcare provider before taking your baby's temperature this way, but it should be done only when advised by your baby’s doctor.
Be sure to use a thermometer that is for rectal use.
Wipe the thermometer with warm, soapy water, then wipe with clear water. Wipe dry or let the thermometer air-dry.
Put a small amount of petroleum jelly or water-based lubricant on the tip.
Use the position that works best for you.
Put baby on his or her back on a firm surface. Hold baby’s ankles and lift both legs, as if changing a diaper.
Or place baby face down across your lap. Use one hand to part baby’s buttocks.
Follow the directions for using your specific digital thermometer.
Gently slip the tip of the thermometer into the anal opening (where stool leaves the body), no further than 1/4 to 1/2 inch.
Hold the thermometer in place until it beeps. Remove it and read the temperature on the display. Slide the thermometer out. Read the temperature on the digital display.
Before putting the thermometer away, clean it with soap and warm water.
When you report your baby's temperature to his or her healthcare provider, make sure you include that the temperature was taken rectally.