Newborn Fever: When to Worry

Your baby’s first illness is never fun.

Having a baby is a time of joy and excitement. Sure, those sleepless nights are tiring, but the newborn smell, baby yawns, and cute smiles cause you to melt into a puddle on a regular basis. Then there are the trying (or downright scary) times, like your baby’s first illness. And fewer things cause more anxiety than a newborn fever.

We know it can be scary, but don’t fret. Read on to find out what can cause a fever in newborn babies, when to worry, and what to do about it.

What is a normal newborn temperature range?

A normal newborn temperature range can vary depending on the time of day and how it’s measured. For rectal readings—the most accurate method—a healthy temperature typically falls between 96.8°F and 100.3°F. It may be lower in the early morning and rise throughout the day.

In newborns, a rectal temperature of 100.4°F or higher is considered a fever. That might sound low, but remember: newborns are tiny and their immune systems are still developing. What wouldn’t be alarming in a toddler can be more serious in an infant.

For babies under one month old, a fever is considered an emergency. While you may not need to call 911, you should go to the emergency room. For older babies, it’s best to consult with your pediatrician for guidance on next steps.

Fever Symptoms in Newborns

Signs of a fever in newborns can vary depending on the child’s immune system and what is causing the fever. In fact, sometimes it can be difficult to recognize a fever in a baby because symptoms can mimic normal newborn behavior.

It’s important to be mindful of any changes in body temperature and take their temperature if you notice these symptoms. And remember, it’s better to be safe than sorry. If you feel like there’s been a rise in body temperature, checking it out causes no harm.

• Crying/Fussiness – For some, this will be the first sign that your child has a fever or illness. Sure, babies cry a lot, but if you’re experiencing a prolonged episode of inconsolable crying, it could be a fever.
• Excessive Fatigue – Newborns already sleep a lot, but if your baby starts favoring naps above eating, a fever could be to blame.
• Reduced Appetite – Most babies will let you know when they’re ready for their next meal. If your baby suddenly has no interest, take their temperature to be safe.
• Cold/Flu Symptoms – If your baby has developed a cough or congestion, check their temperature, too. (Then notify the pediatrician.)
• Spitting Up – Again, spit-up is normal in babies, but if it’s more frequent and in excess quantities, this could point to vomiting rather than spitting up.
• Feeling Warm – This seems obvious, but it can be hard to gauge the baby temperature accurately, especially on a warm day. Taking their temperature internally (rather than just feeling their forehead) is the best way to be sure.
• Pulling at Ear – Ear infections can cause discomfort in the ears. Because a baby cannot communicate with words, pulling at their ear is a tell-tale sign that they are feeling pain or discomfort in that area.
• Rash – Any type of rash should be evaluated by your pediatrician, especially if your baby has been exposed to or has chickenpox symptoms.

Causes of Newborn Fever

Remember, a fever is a symptom, not an illness. A newborn fever is a clue that something else is going on.

• Common Virus: Babies are especially vulnerable to viruses, so it’s easy for them to pick up a cold or flu. While friends and family may want to meet your new baby, ensure all visitors wash their hands and stay home if they’re sick.
• Overheating: Babies can display a fever if they’re overdressed. Although many parents believe babies need multiple layers, babies are quite good at regulating their body temperature. Dress your baby in one extra layer than you’re wearing—for example, if you’re in short pajamas, dress them in long pajamas plus a swaddle.
• Dehydration: In the first few days, babies can become dehydrated if mom’s milk hasn’t come in or formula adjustments haven’t been sorted. This is why pediatricians ask how many wet/dirty diapers a baby has each day.
• Bacterial Infections: These are a serious cause of fevers in newborns and a reason why a fever can be an emergency. Since newborns cannot communicate, it requires a doctor’s expertise to determine the cause. Bacterial infections may include spinal infections, urinary tract infections, and bacterial meningitis.

It’s also important to note that as common as the old wive’s tale is, teething is not a cause of a fever.

How To Take Your Newborn’s Temperature

Ear and forehead thermometers are easy to use, but rectal thermometers are the most accurate. Why? Unlike the ears and skin, the rectum is not influenced by outside factors such as a cool day or sun exposure. (If all you have is a forehead or ear thermometer, that’s fine, too.). A normal newborn temperature on the forehead is again, between 96.8 and 100.4 degrees Fahrenheit.

First, clean the thermometer with alcohol or soap and water. Gently lay your newborn on their tummy with their knees underneath them or on their back, holding their feet above their head.

If you want to use a little petroleum jelly or coconut oil to help glide the thermometer, that’s fine but not necessary. The tip of the thermometer should only go in ½-1 inch. Do not go further than this, as you could puncture the baby’s rectum walls.

Wait until the thermometer beeps and read the temperature. If it’s above 100.4, and the baby has been unbundled for 10 minutes, it’s time to call the doctor.

How To Treat a Newborn Fever

For newborns—that is, babies under one month old—it’s crucial to consult with your pediatrician first.

If your baby is under one month (or four weeks) they may instruct you to head to the emergency room to test for bacterial meningitis. (It’s not common, but it’s best to rule it out.)

If we are speaking about older babies, then your doctor will probably tell you to try some acetaminophen (Tylenol) to bring the fever down. Always check with your pediatrician (or the dosing instructions) for the proper amount.

You can also give your baby some lukewarm baths—not hot, not cold. Dress them in light clothing and make sure they’re getting plenty of hydration. If your baby is breastfed, there is no harm in feeding them more than usual (if they’re interested).

Staying Calm and Confident Through Baby’s Fever

Whether you’re a first-time parent or a seasoned pro, newborn fevers are never ideal.
You’re already stressed enough with the diapers, lack of sleep, and constant crying. Adding an illness to the mix is the last thing you need. Make sure to follow the advice above, don’t Google too much, and call your pediatrician.

Call us today if you have a question or need an appointment so that we can help your baby on their way back to health.