How do I take my newborn’s temperature?
Newborn fevers can be scary. If you suspect your newborn may have a fever, it is important to take their temperature and seek medical advice. If your infant has a rectal temperature of 100.4°F (38°C), they have a fever and need medical care. Infants under 12 weeks with a fever should be seen by a medical professional immediately.
There are several ways to take your newborn’s temperature, however, their rectal temperature is considered the most accurate. If your baby is moving around too much or you feel uncomfortable with taking a rectal temperature, you can take their temperature under their armpit or use an infrared thermometer. Studies show that armpit and forehead temperatures are approximately 0.3 to 0.6° C (0.5 to 1° F) lower than rectal temps, therefore you should add at least 0.3° C (0.5° F) to your reading. In-ear (tympanic) thermometers are too large for newborn ears and I do not recommend them.
What about those pacifier thermometers?
Studies have proven that readings from pacifier thermometers are as accurate as forehead or armpit temperature readings. The challenge with pacifier thermometers is that you cannot hold them in place for your baby. The baby must be able to actively hold the pacifier in their mouth for the full duration of the reading. If you have a newborn who loves their pacifier, this might be an excellent and non-invasive way to take their temp.
How to take your newborn’s rectal temperature:
Supplies
Digital thermometer with a flexible tip
Water-based lubricant
Alcohol wipes
Another adult (optional)
Steps
Clean the thermometer with alcohol wipes before and after use or carefully wash the tip with soap and warm water (being careful to avoid getting water in the battery compartment)
Apply a small amount of lubricant (such as Vaseline or Aquaphor) to the thermometer's tip
Position the baby on their back and lift their legs to expose their rectal area. It can be helpful to have a second adult there to hold their body still and soothe them.
Insert the thermometer tip into the baby's anus about half an inch
Hold the thermometer in place until it is finished.
Remove the thermometer and read the temperature.
Clean the thermometer with soap and water or alcohol wipes.
Tip: Designate one thermometer for rectal temperatures and write R or Rectal in permanent marker.
How to take a newborn's axillary or armpit temperature
Supplies
Digital thermometer
Alcohol wipes
Another adult (optional)
Position the baby on their back or have another adult hold them upright, facing outward.
Place the thermometer in the center of the baby's armpit, under their clothes.
Hold the baby's arm against their body to keep the thermometer in place.
Leave the thermometer in place for the recommended time specified in the thermometer's instructions.
Remove the thermometer and read the temperature. Add 0.3 to 0.6° C (0.5 to 1° F) to the reading.
Clean the thermometer with soap and water or alcohol wipes.
How to take your child's temperature. American Academy of Pediatrics. https://patiented.solutions.aap.org/handout.aspx?resultClick=1&gbosid=166297. Accessed August 14, 2024
Braun CA. Accuracy of pacifier thermometers in young children. Pediatr Nurs. 2006 Sep-Oct;32(5):413-8. PMID: 17100072.
Beckstrand RL, Wilshaw R, Moran S, Schaalje GB. Supralingual temperatures compared to tympanic and rectal temperatures. Pediatr Nurs. 1996 Sep-Oct;22(5):436-8. PMID: 9087077.
