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by: Meredith Stedham, RN, LPC

Taking Your Baby’s Temperature

Many new parents have the experience of casually kissing their baby on the forehead followed by uncertainty and the thought, “you feel warm!”  Since human lips are very sensitive and contain many nerve endings, fevers are often first detected this way.  Parents often ask me what to do is this situation, especially with a small newborn baby.  While taking the temperature of an adult is relatively simple, the options of how to take a baby’s temperature can quickly overwhelm parents.  Which type of thermometer should be used from the stockpile gathered at the baby shower… the plain digital one, a pacifier, the “ear thing”, or what about the one that scans across the forehead?  Then once you choose one of these devices, how do you know if it is accurate and whether to call the doctor?  Whichever of the following choices parents select, it is important to know how to use each thermometer correctly to get an accurate reading and to also follow the manufacturer’s recommendations.

*Digital Thermometers: Usually provide the quickest and most accurate readings.  A digital thermometer can be used to take rectal (in the rectum), oral (in the mouth), or axillary (in the armpit) temperature.  The tip of the thermometer can be cleaned with soap and cool water or with rubbing alcohol.  When taking an oral temperature, wait 20-30 minutes after your child eats or drinks any fluids before taking an oral reading.
*Rectal Thermometers: Can be a standard digital thermometer, or sometimes may be a variation of a shorter digital thermometer that is specifically designed for rectal readings.  There are some relatively affordable rectal thermometers that provide “rapid read” results of around 8 seconds, which can be reassuring to nervous parents.  Place your child belly-down across your lap or on a flat surface and keep your palm along the lower back; or you may lay your child face-up with legs bent toward the chest and your hand on the back of the thighs.  Your other hand will remain on the thermometer until you hear the appropriate number of beeps signaling that the temperature can be read.  The tip of rectal thermometers should be lubricated with a small amount of petroleum jelly or KY Jelly prior to use, and the tip should be inserted ½ inch to 1 inch into the anal opening.  Stop if you feel any resistance.  NOTE:  When using a digital thermometer to take a rectal temp, it is wise take a permanent marker and write “RECTAL” and the child’s name on the thermometer and the outside plastic case in order to avoid that thermometer from ever being used for oral temperatures in the future!!
*Tympanic (ear) Thermometers: Measure the temperature inside the ear canal.  Although they provide quick and easy readings for older infants and children, tympanic thermometers are not as accurate in newborns and young infants because of the size and shape of their ear canals.  Too much earwax can also cause an inaccurate reading.  Tympanic thermometers should not be used immediately after a child has been swimming, taken a bath, or if the child has any ear pain.  NOTE:  It is important for parents to follow the manufacturer’s guidelines and use the correct technique for a tympanic thermometer in order to obtain an accurate reading.
*Temporal Artery (forehead) Thermometers:  The sensor is “scanned” across the forehead to read the temperature.  While these thermometers have quickly gained popularity with parents because of their ease of use, the reliability of temporal artery thermometers has not yet been verified.
*Pacifier Thermometers: Again, these may seem like another convenient option to parents, however they are not as accurate as a rectal thermometer.  The pacifier thermometer should not be used in infants younger than 3 months.
*Glass Mercury Thermometers:  The AAP now advises these not be used in order to prevent accidental exposure to mercury, which is an environmental toxin.

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According to the American Academy of Pediatrics, taking a rectal temperature provides the most accurate reading for children younger than 3 years.  Obviously, it is common for both parents and toddlers to have anxiety about doing anything that starts with the word “rectal.”  Therefore, often parents choose to use an alternate method of measuring temperature in older infants and children.  Following are some general guidelines as recommended by the AAP to help parents in determining the best option depending on their child and circumstances.

Birth to 3 Months:  Rectal temperature using a digital thermometer is the standard for getting an accurate reading for all newborns and babies younger than 3 months.  (For premature babies, consult your physician.)  NOTE:  It is not recommended to do excessive consecutive rectal readings because the repeated insertion of the thermometer to the rectum can potentially cause inflammation or other complications.  To put it more simply, parents should not check a rectal temperature unless there is concern of a fever.   (Consult your physician for any questions regarding taking a rectal temperature.)
3 Months to 3 Years: Rectal temperature using a digital thermometer is still the most accurate method.  The tympanic (ear) thermometer and axillary digital thermometer can also be used, however they are not as accurate.
4 to 5 years: At around age 4 or 5 parents can feel comfortable taking their child’s oral temperature with a digital thermometer.   Axillary, tympanic, and rectal thermometers are also options for this age.
5 years and older: Oral, axillary, and tympanic thermometers are all acceptable choices as long as they are measured correctly.

Parents should consult their physician about the most appropriate and accurate way to measure their child’s temperature as well as asking for the guidelines of when to call the physician concerning fevers. The general guideline for newborns up to 3 months is to call your healthcare provide for a rectal temperature of 100.4 degrees or higher.   In addition to these recommendations based on age and method of taking your child’s temperature, there are a few more tips to keep in mind.

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*If you notice your child feels warm and you are concerned they may have a fever, consider the circumstances.  Is your baby in warm pajamas while wearing a hat and wrapped in 4 layers of a swaddle blanket?  Is the room warm or lacking good air flow?  For older children, have they been running through the house for 20 minutes or just finished playing outside?
*Never leave an infant or child unattended during the measuring of their temperature.
*TRUST YOUR PARENTAL INSTINCTS!!!  If your child clearly has a fever, the decision to contact the doctor is simple.  However, when there is no fever or a “low grade” fever (for example 99.6 degrees), parents should consider all relevant information.  If your child is lethargic, has vomiting or other GI issues, or any other symptoms that concern you then consider contacting your physician.  You know your child better than anyone else… therefore trust your gut when making decisions about seeking medical care.

For more information on these topics, you can visit the website for the American Academy of Pediatrics at, or the parent-friendly website sponsored by the AAP:

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