Newborn with Fever

What Is An Infant Fever?

Fever in newborns and infants is any temperature of 100.4 degrees Fahrenheit and higher. The normal temperature range for infants is between 97 to 100.3 degrees Fahrenheit. Your baby develops a fever to fight off germs. Most babies look flushed and feel warmer when they have a fever. Loss of appetite, crankiness, body aches, sweating, and shivering are all common effects of a fever. If your baby experiences a fever, please contact your doctor right away.


A high fever will likely affect your baby in observable ways. Your baby will often act and respond to familiar activities such as eating, sleeping, and playing differently than usual.

The following infant fever symptoms indicate that your baby has a high temperature:

  • Crankiness
  • Loss of appetite
  • No interest in play
  • Trouble sleeping
  • Tired or lethargic
  • Sweating
  • Inconsolable
  • Shivering
  • Convulsions
  • Seizures
  • Fewer wet diapers
  • Rash
  • Vomiting
  • Diarrhea
  • Looks ill
  • Sore throat
  • Ear infection
  • Body aches
  • Headaches


What causes fever in babies? The three main causes of fever in newborns and infants are infections, overheating and dehydration.

Each one of these “fever in baby” causes has unique characteristics:

  • Infection – A fever usually means that your baby’s immune system is working and fighting off an infection. Approximately half of babies with an infection have a fever.
  • Overheating – Babies can easily and quickly become overheated when near a heater or bundled under layers of clothing and blankets. This can occur at home or in a heated car.
  • Dehydration – When a baby does not get enough fluids, their temperature can rise and cause a fever. Dehydration is the extreme loss of water in the body. Dehydration can lead to severe complications so medical attention is highly recommended.

How Do I Take My Baby’s Temperature?

You can take your baby’s temperature orally, rectally, axillary or at the temples. Orally is by inserting the thermometer in your baby’s mouth. Rectally is taking your baby’s temperature in their rectum. Axillary is taking your baby’s temperature under their arms or in their ear. It is helpful to avoid mercury thermometers as they can break and lead to mercury exposure or poisoning.

Rectal thermometers are ideal for infants. To take a rectal temperature with a digital thermometer, wash the thermometer with soap and water. You can also wipe it clean with rubbing alcohol. Next, lay your baby on their belly or back with their legs angled toward their chest. Add a small portion of petroleum jelly to the end of the thermometer before gingerly inserting it into the rectal opening. Hold the thermometer in the rectum for 2 minutes. The digital thermometer may alert you with a beep or chirping sound at the end of two minutes. Slowly and gently remove the thermometer to read the temperature. We recommend that you clean the thermometer after each use.

When to see a doctor for a baby with a fever:

Anytime your baby experiences the symptoms a fever, we recommend that you contact your doctor for further recommendations. Fever in infants can be serious.

Please also consider the following suggestions based on specific circumstances:

  • If your baby is under two months old and experiences a fever, please go to the emergency room immediately.
  • If your baby is two to three months old, we recommend that you call your baby’s doctor as soon as possible.
  • If your baby is three or more months old and experiences severe fever symptoms, such as inconsolable, difficult to awaken, dehydrated, severe pain, etc., please call your doctor right away.


Get in touch with your baby’s primary care doctor anytime your baby experiences a fever. Taking your baby to the hospital is not always necessary.

If your baby does not need treatment in a medical setting, there are several ways to treat your baby at home:

  • Dress your baby in light or thin clothing.
  • Help your baby get plenty of fluids.
  • Give your baby a bath in lukewarm water. Never give a baby with a temperature a bath in cold water. This may cause chills, shivering, and may even increase their temperature.
  • Give your baby a sponge bath.
  • Use a gentle fan on a low setting to cool your baby.
  • Avoid giving your baby any medication, even over-the-counter medication, without first consulting a pediatrician. Some common medications can be harmful and even life-threatening to infants.

You may want to check your baby’s temperature after you implement one or more of these treatments. If you find that you want medical care, Baptist Health is here to help.

Next Steps with MyChart

Discover MyChart, a free patient portal that combines your Baptist Health medical records into one location. Schedule appointments, review lab results, financials, and more! If you have questions, give us a call.