As adults, we have a thermostat that is tightly controlled, which assists us in maintaining a consistent internal temperature. When our body temperature is too low, we shiver in an effort to bring it up, and when it is too high, we sweat in an effort to bring it back down to a more comfortable level. On the other hand, newborns do not yet have fully developed versions of these mechanisms. In addition to this, newborns do not have the insulating layer of fat that later developing babies and children do.
Because a newborn’s system for regulating temperature is not fully developed, fever may or may not develop in response to an infection or illness. Fever in infants can be caused by a variety of other conditions, some of which are even more concerning. If your baby is younger than two months old and has a rectal temperature of 100.4 degrees or higher, you should contact your baby’s doctor as soon as possible. Your physician needs to examine you as soon as possible regarding this matter.
A rectal temperature of 101 degrees or higher is considered to be a fever in infants and young children who are older than infants. If your child is between three and six months old and has a temperature of 101 or higher, you should call the doctor. Temperatures of 103 degrees or higher should prompt a call to the doctor for infants and children older than 6 months; however, if associated symptoms are present, it is more likely that these symptoms will prompt a call. A rectal temperature between 99 and 100 degrees is considered a low-grade fever, and most of the time, it does not require the attention of a medical professional.
Normal temperature hovers somewhere close to 98.6°F (37°C). This temperature can vary slightly from morning to evening. Body temperatures are generally lower when you wake up and higher in the afternoon and evening.
Infants under 3 months old with a fever require immediate medical attention to diagnose the underlying cause and treat it if necessary.
Infants are considered to have a fever if their temperature is:
- 100.4°F (38°C) or higher when taken rectally
- 99°F (37.2°C) or higher when taken by other methods
Low-grade fevers don’t always require a visit to your doctor for infants older than 3 months.
A slightly elevated temperature in an infant older than 3 months may not require a trip to the doctor. You may be able to treat the fever at home with the following methods:
If your child is over 3 months, you can offer them a safe amount of children’s acetaminophen (Tylenol).
Doses are usually based on weight. Your doctor may recommend weighing your baby if they haven’t recently been weighed or if they’ve had a recent growth spurt.
If your baby isn’t uncomfortable or fussy from their fever, you may not need to give them any medication. For higher fevers or other symptoms that are making your infant uncomfortable, medication can help them temporarily feel better.
2. Adjust their clothing
Dress your infant in lightweight clothing and use just a sheet or light blanket to keep them comfortable and cool.
Overdressing your infant may interfere with their body’s natural methods of cooling down.
3. Turn down the temperature
Keep your home and your infant’s room cool. This can help prevent them from overheating.
4. Give them a lukewarm bath
Try sponging your baby down with lukewarm water. (Water temperature should feel warm, but not hot, to the touch on your inner arm.) Maintain constant supervision during bathing to ensure water safety.
Avoid using cold water, as this can lead to shivering, which may increase their temperature. Dry your baby off immediately following the bath and dress them in lightweight clothing.
Alcohol baths or wipes to lower fevers aren’t recommended and can be harmful.
5. Offer fluids
Dehydration is a possible complication of fever. Offer regular fluids (breast milk or formula) and make sure your baby has tears when crying, a moist mouth, and regular wet diapers.
Call your doctor’s office to discuss ways to keep your child hydrated if this is a concern.
There are several things you should not do if your infant has a fever:
- Do not delay medical attention for a newborn with any fever or an infant with a persistent fever or who seems very ill.
- Do not administer medication to your infant without first checking their temperature and consulting your doctor’s office.
- Do not use medication intended for adults.
- Do not overdress your infant.
- Do not use ice or rubbing alcohol to lower your infant’s temperature.
To get the most accurate temperature, use a digital multiuse thermometer rectally. Keep in mind that a rectal temperature will be higher than temperatures taken with other methods.
Here’s how to take your infant’s temperature rectally:
- Read the manufacturer’s instructions initially and set the measurements to either Fahrenheit or Celsius (in order to report the temperature correctly).
- Clean the thermometer with rubbing alcohol or soap.
- Coat the end of the thermometer in petroleum jelly or another safe lubricant.
- Remove any clothing or diaper from your infant’s bottom.
- Lay your infant on their stomach on a safe and comfortable surface, such as a changing table or bed, or on your lap.
- Hold your infant gently in place while you take the temperature. Don’t let them move or wiggle during the process to avoid the thermometer moving further into your infant’s rectum. Having someone’s help to hold the infant still is best to prevent injury.
- Turn on the thermometer and insert it only a half inch to 1 inch into your infant’s rectum until the thermometer beeps. (Most thermometers have a visual notch or safety guide that demonstrates a safe limit for rectal insertion.)
- Pull out the thermometer carefully and read the temperature.
Other devices may provide accurate temperature readings for your infant if you use them according to their instructions.
Temporal artery thermometers measure the temperature from the forehead and may not work for infants younger than 3 months old. A rectal temperature is recommended for infants of this age group.
Tympanic thermometers read the temperature from a baby’s ear and should only be used in infants 6 months and older.
Here are a few other guidelines for taking your infant’s temperature:
- Designate your digital multiuse thermometer for rectal use only and label it to avoid confusion.
- Avoid taking your infant’s temperature orally or under the armpit. These aren’t considered accurate for infants and young children.
- Don’t conclude that your infant has a fever if you feel warmth by touching their forehead. You need an accurate digital thermometer reading to determine fever.
- Avoid using mercury-filled thermometers. They pose a risk of mercury exposure if they break.
Make sure to monitor your infant’s temperature during the course of an illness and observe other symptoms and behaviors to determine whether you should contact your doctor.
You should contact your infant’s doctor or seek medical treatment if:
- your infant under 3 months old develops any elevation in temperature
- your infant between 3–6 months old has a rectal temperature of 102°F (38.9°C) or higher
- your 6- to 24-month-old has a fever above 102°F (38.9°C) for more than a day or two with no other symptoms
- they have a fever that has lasted longer than 24 hours or that occurs regularly
- they’re irritable (very fussy) or lethargic (weak or more sleepy than usual)
- your infant’s temperature doesn’t lower within an hour or so after taking an appropriate dose of medication
- they develop other symptoms like a rash, poor feeding, or vomiting
- they’re dehydrated (not producing tears, spit, or the usual amount of wet diapers)
Fevers are generally a symptom of a larger medical condition.
Your infant may develop a fever for many reasons, including from:
- a viral infection
- a bacterial infection
- certain vaccinations
- another medical condition
Does teething cause fevers?
Teething isn’t considered a cause of fever. It may be that your teething infant has another underlying condition causing the fever.
Treating a fever in an infant will vary based on the age of the child and the symptoms surrounding the fever.
Newborns must be seen by a doctor immediately if they develop a fever, while older infants may be treated at home if they develop a mild fever.
Always check with your doctor before giving any medication to your infant, and see a doctor if your child develops a high fever or if the fever lasts longer than a day or two.
Signs of Fever in Newborn
Your infant will likely feel hot and appear flushed when they have a fever. In addition to headaches and body aches, a fever may cause you to sweat or shiver. When a child has a fever, some of them will get headaches, but the majority of them will lose their appetite. Some children simply report feeling sleepier than they normally do.
Fever in newborns may be due to:
- InfectionFever is a normal response to infection in adults, but only about half of newborns with an infection have a fever. Some, especially premature babies, may have a lowered body temperature with infection or other signs such as a change in behavior, feeding, or color.
- OverheatingWhile it’s important to keep your baby from becoming chilled, your baby can also become overheated with many layers of clothing and blankets. This can occur at home, near heaters, or near heat vents. It can also occur if your baby is over-bundled in a heated car. Never leave your baby alone in a closed car, even for a minute. The temperature can rise quickly and cause heat stroke and death.If your baby is overheated, he or she may have a hot, red, or flushed face, and may be restless. To prevent overheating, keep rooms at a normal temperature, about 72 to 75 degrees, and dress your baby the same way you feel comfortable at that temperature.
- Low fluid intake or dehydrationSome babies may not take in enough fluids, which causes a rise in body temperature. This may happen around the second or third day after birth. If fluids are not replaced with increased feedings, dehydration (excessive loss of body water) can develop and cause serious complications. Intravenous (IV) fluids may be needed to treat dehydration.
In extremely rare cases, fever can signal a life-threatening disease called bacterial meningitis. If your infant has a fever greater than 101 degrees and is lethargic or you can’t get him or her to wake up normally, you should take your infant to the emergency room immediately.
Taking Baby’s Temperature
For babies and toddlers up to 3 years old, taking the temperature rectally, by placing a thermometer in the baby’s anus, is best. This method is accurate and will give a quick reading of your baby’s internal temperature.
Underarm temperature measurements may be used for babies ages 3 months and older. Other types of thermometers, such as ear thermometers, may not be accurate for newborns and require careful positioning to get a precise reading. Skin strips that are pressed on the skin to measure temperature are not recommended for babies. Touching your baby’s skin can let you know if he or she is warm or cool, but you cannot measure body temperature simply by touch.
Oral and rectal thermometers have different shapes and one should not be substituted for the other. Do not use oral thermometers rectally as these can cause injury. Rectal thermometers have a security bulb designed specifically for safely taking rectal temperatures. To take your infant’s rectal temperature, follow these steps:
- Place your baby across your lap or changing table, on his or her stomach, facing down. Place your hand nearest your baby’s head on his or her lower back and separate your baby’s buttocks with your thumb and forefinger.
- Using your other hand, gently insert the lubricated bulb end of the thermometer one-half inch to one inch, or just past the anal sphincter muscle. Stop immediately if the thermometer meets resistance.
- The thermometer should be pointed toward your baby’s navel.
- 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 moving.
- Never leave your baby unattended with a rectal thermometer inserted. Movement or a change in position can cause the thermometer to break.
- Hold the thermometer for at least 1 minute or until an electronic thermometer beeps or signals.
- Remove the thermometer.
- Wipe the bulb.
- Read the thermometer immediately and write down the temperature, date, and time of day.
- Disinfect the thermometer with rubbing alcohol or an antiseptic solution.
If your baby’s temperature is 100.4 degrees or higher, make sure he or she is not crying or dressed too warmly. Retake your baby’s temperature again in about 30 minutes. If the temperature is still high, call your baby’s doctor immediately.
How To Treat A Fever
If your baby’s temperature doesn’t warrant a call to the doctor, there are steps you can take at home to help lower the fever:
- Bathe your baby in lukewarm water. Never use cold water or alcohol to bathe your baby because it may cause shivering and actually increase body temperature.
- Dress your baby in light, comfortable clothing.
- Make sure your baby is getting enough fluids to prevent dehydration.
- NEVER give your baby aspirin to treat a fever. Aspirin has been linked to Reye’s syndrome, a rare but potentially serious illness that affects the nervous system and can be debilitating or even fatal in children.
- Acetaminophen and ibuprofen are the two medications for children that help fight fever. Acetaminophen can be given to infants over 3 months without calling the doctor but children less than 6 months old should not be given ibuprofen. Read the instructions on the package or ask your doctor to be sure you give appropriate doses. Do not give more than the recommended dose of either medication. If your child is vomiting or dehydrated be sure to consult your pediatrician.