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Did you know that newborns are not prepared to handle changes in body temperature like adults and older children?

As adults, we have more control over our body temperature. When we are too cold, we shiver to warm up. When we're too hot, we sweat to help cool down.

Over time, newborns will develop this same ability to regulate their body temperatures. Until then, parents should monitor their infant's body temperature for signs of fevers, which could indicate a more serious complication or disease.

Fever Warning Signs

The age of your baby helps determine fever. Here are guidelines for infants and children of different ages: 

  • Older than one year, call your child's physician if a fever lasts longer than 24 – 48 hours (or if the fever is accompanied by any other worrisome symptoms).
  • 3 – 6 months old, call the doctor if your baby's temperature exceeds 101° Fahrenheit.
  • Younger than 3 months, call your child's doctor immediately if your child has a temperature of 100.4° or higher.

A temperature of 100.4 or higher in an infant less than 29 days old is a medical emergency.


What Causes Fevers in Babies?

Your baby's ability to regulate body temperature is not yet fully developed. Fever should be used as a warning sign that something may be wrong. Some causes of fever include:

Fevers are a common symptom of infections in adults and children, however only about half of newborns with an infection will show a fever. If your child was born prematurely, he or she may have a lowered body temperature with infection or other signs such as a change in behavior, feeding, or color.

Some well-meaning parents use too many blankets or clothing layers fearing their baby is not warm enough. In some cases, these extra layers may cause your newborn to become overheated. Overheating can occur:

  • At home, near heaters, or near heat vents.
  • In the car if your child is over-bundled or if it is warm outside

If your baby is overheated, he or she may have a hot, red, or flushed face. To prevent overheating, keep rooms at a normal temperature, about 72 to 75 degrees. A good guideline is to dress your baby in 1 layer more than you are comfortable in. 

Low fluid intake or dehydration
A rise in body temperature in newborns can also be caused by dehydration, an excessive loss in body water. Be extra vigilant during the second or third day after birth to ensure that your child is taking in enough fluids. The fluids should be in the form of breast milk or formula. Never give your baby any other type of fluids without first talking to your doctor.

If fluids are not replaced with increased feedings, dehydration may occur. In extreme cases, intravenous (IV) fluids may be needed to treat dehydration. 

If your baby is not creating at least 4 wet diapers a day, contact your child's physician for evaluation. 

Bacterial Meningitis
While it is rare, a fever could be an indication that your infant has bacterial or viral meningitis.

This disease can be severe and life-threatening, depending on the cause.  If suspected, physicians may evaluate your child to determine if this is present.

Taking Your Baby's Temperature

If your baby or toddler is 3 years old or younger, then taking the temperature rectally by placing the thermometer in the baby's anus is best. This method is accurate and will give a quick reading of your baby's internal temperature.

Oral and rectal thermometers are designed differently and should never be used interchangeably. Avoid using oral thermometers to measure your child's temperature rectally as this may cause injury or discomfort.

To take your infant's rectal temperature, follow these steps:

  1. Lay your baby on his or her stomach facing down across your lap or changing table. Place your hand nearest your baby's head on his or her lower back and separate your baby's buttocks with your thumb and finger.
  2. Using your other hand, gently insert the lubricated bulb end of the thermometer one-half inch to one inch to just past the anal sphincter muscle. Stop immediately if the thermometer meets any resistance.
  3. Point the thermometer toward your baby's naval.
  4. Hold the thermometer with one hand on your baby's buttocks so the thermometer will move with your baby. Use the other hand to comfort your baby and prevent movement.
  5. Never leave your baby unattended with a rectal thermometer inserted. Sudden movements or a change in position can cause the thermometer to break.
  6. Hold the thermometer for at least one minute or until the thermometer's electronic timer beeps or signals.
  7. Remove the thermometer and wipe the bulb.
  8. Read the thermometer immediately and write down the temperature, date, and time of day.
  9. Disinfect the thermometer with rubbing alcohol or a similarly strong antiseptic solution.

Different types of thermometers
Many types of thermometers are available: rectal, oral, ear and forehead are some of the options.

  • Underarm thermometers can be used to measure the temperatures of babies ages 3 years and older.
  • Other types of thermometers such as ear thermometers may not be as ideal for newborns and require careful placement of the device to get an accurate reading.
  • Skin strips that are pressed onto the skin to measure temperature are not recommended for babies.

Treating Your Baby's Fever

Use the guidelines above for calling the doctor. In the interim, some steps you can take to lower your baby's temperature are:

  • Give your child a bath in lukewarm water. Avoid baths with cold water or alcohol because it may cause your child to shiver and actually increase body temperature.
  • Change your child into clothing that is light and comfortable
  • Ensure that dehydration is not to blame by giving your child enough fluids

Over-the-counter fever medications
Both acetaminophen and ibuprofen can be used – in appropriate dosages - to fight fevers.

  • Acetaminophen can be given to infants over 3 months.
  • Babies younger than 6 months old should not be given ibuprofen. 

Always read the instruction on the bottle or packaging and check with your doctor to make sure you are providing the appropriate dose. Do not give more than the recommended dose of either medication and do not give more frequently than recommended.

Never give your child aspirin to treat a fever.

Aspirin is linked to Reye's Syndrome, a rare but potentially serious illness that affects the nervous system and can be debilitating or even fatal for children.

As your baby's parent, you know your child better than anyone else. If your child has unusual behavior or symptoms, always consult your doctor.

Emily Bendlin, MD

Methodist Physicians Clinic - Gretna

Dr. Bendlin loves working with kids and their parents. She has always enjoyed caring for kids.  "I've always liked medicine, but more importantly I've always liked kids," Dr. Bendlin said. "During my pediatric rotation it was the 'aha' moment. It was so fun and I was so excited when I went home. I knew at that time this is it for me – pediatrics is where I’m supposed to be." According to Dr. Bendlin, "Working with kids is fun. What other ...

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