Fever in Babies: When to Worry and When to Wait
Not every fever requires a trip to the ER. Learn how to read your baby's temperature, what counts as a dangerous fever, and when to call your pediatrician.
What Temperature Is Considered a Fever?
A fever is generally defined as a rectal temperature of 100.4°F (38°C) or higher. For babies under 3 months old, any fever is a medical emergency and you should call your doctor immediately.
How to Take Your Baby's Temperature Accurately
For infants under 3 months, a rectal thermometer gives the most accurate reading. Digital thermometers are safe and fast. Ear and forehead thermometers can be used for older babies but may be less accurate for newborns.
When to Call the Doctor Immediately
- Baby is under 3 months old with any fever
- Temperature is above 104°F (40°C) at any age
- Baby is unusually difficult to wake
- Baby has a stiff neck, rash, or difficulty breathing
- Fever lasts more than 2 days
Home Care for Mild Fevers
For babies older than 3 months with a mild fever (100.4–102°F), you can often manage at home. Keep them hydrated, dress them lightly, and offer extra nursing or bottle feeds. Ask your doctor before giving any fever-reducing medication.
What Causes Fevers in Babies?
Most fevers in babies are caused by viral infections like the common cold or flu. Less commonly, bacterial infections such as ear infections or urinary tract infections can cause fevers and require antibiotic treatment.
The Bottom Line
Trust your instincts. If your baby seems unwell beyond just a high temperature, or if something feels "off," always contact your pediatrician. It's always better to check than to wait.