It’s scary when your baby has a fever. A newborn is too small and vulnerable, and a newborn’s immune system hasn’t developed yet either.

But when do you start to worry? Fever in babies happens for multiple reasons, and there’s a time to let it pass and a time to call a medical professional. What are those times?

Here’s a look at fever in babies, what causes it, how to treat it, and when you need to reach out to a pediatrician — or seek urgent care.

When in doubt, call the doctor. There’s no reason to put a baby at risk. I’ve outlined some of the accepted parameters below, but a parent is typically in-tune with a child. If you’re worried enough to think you should call the doctor, you need to go ahead pick up the phone. If you need another resource on this topic, I recommend following the Mayo Clinic’s guidelines on when to contact your child’s doctor.


What is Considered a Fever for a Baby?

If you’re looking for a baseline on what is considered a fever for a baby, here it is: 100.4 degrees Fahrenheit via a rectal thermometer.

Why a rectal thermometer? Because they are the most accurate. And when you’re taking the temperature of a baby, accuracy is extremely important. Just a degree or two can be the difference between “nothing to worry about” and “time to call the doctor.”


What Causes a Baby Fever?

The causes of baby fever fall into two broad categories. First, baby fever can be caused by a viral infection, such as a cold or the flu or even a stomach bug. Viral fevers tend to last for about three days, and there’s not much you can do for them — antibiotics won’t work.

A bacterial infection can also cause baby fever. Think along the lines of pneumonia or an ear infection. In these cases, you can use antibiotics to fight the fever (and the infection). That said, bacteria-related fevers are less common than virus-related fevers.


How to Bring Down a Baby Fever

First, know that it’s impossible to truly treat a fever. You can only help reduce the fever in the short-term — masking it, in essence.

For a child under 6 months, Tylenol is the only fever reducer you can use. Once your baby is beyond 6 months, you can try other medications like Advil.

You can also try approaches that aren’t related to medicine, such as using a cool washcloth to dab at your baby’s forehead. Just don’t use anything that’s going to make your child shiver. Also, have him or her drink as much fluid as possible to help fight against dehydration.


When to Call the Doctor for a Baby Fever

A fever in a baby isn’t anything to mess around with. Make sure to call a doctor immediately if your baby under 3 months has a fever of more than 100.4 (as taken rectally), or if a fever lasts longer than 24 hours. Between 3 and 6 months, 101 is the danger line. Beyond 6 months, call the doctor if your child’s fever reaches the 102 or 103 range.

Also, you need to be extra careful when your baby is under 3 months old because the child’s immune system isn’t fully developed. If you take a rectal temperature of 100.4 or more in a child under 3 months, take action immediately. If it’s the middle of the night and you can’t reach your doctor, try an urgent care location to get the attention your child needs.


When to Take a Baby to the Hospital for a Fever

Taking your baby to the hospital is another step you can take. But make sure that step is needed. Look for danger signs that include:

  • Fevers of 105 degrees Fahrenheit or more
  • Difficulty breathing
  • Trouble swallowing
  • Lethargy
  • Seizure

You never want to be the parent that overreacts, but you also don’t want to be the parent that puts his or her child at risk. Trust your instincts. If your child is displaying symptoms of fever that cause concern, take immediate action to get your child medical attention.


Final Thoughts on Fever in Babies: When to Worry

I hate the word “worry,” though that’s exactly what we do as parents. Just make sure you don’t panic. If you are worried, call a doctor. That’s why we have medical professionals to help us. If you can’t get a hold of your doctor, run up to an urgent care location. It’s better to have a medical professional look at your child than to sit around worrying at home.

Do you have anything to add to the information above? Let us know in the comments section, or send us a message using our contact form.