01/17/2026
Fever is the #1 reason pediatricians get called at night, and yes, your baby will have one. When it happens, anxiety is completely normal. This flow chart is here to help you think clearly in the moment.
First, let’s define fever:
👉 100.4°F or higher taken rectally
🚨 Critical age rule:
Birth to 28 days: Any fever of 100.4 or greater is an emergency. Call immediately.
Most fevers are caused by infections. When that happens, the immune system kicks into high gear raising temperature, heart rate, and breathing rate to help fight it off. Important reminder: fever itself is not bad. It’s often the first sign your baby’s body is doing its job.
Babies from birth to 28 days of life with a fever are universally admitted to the hospital for evaluation and monitoring.
Babies from 1-3 months of age still need to be evaluated urgently if they have a fever to figure out what’s going on.
Babies from 3-6 month of age with higher fevers of 102 F or there is no obvious cause (a new runny nose or cough) should check in with their healthcare provider.
After 6 months of age, it’s usually not how high the fever is that matters most, but rather how your baby looks and if it is obvious that your baby has a garden variety virus of the week (runny nose, cough, etc). If your baby still looks unwell after fever-reducing medicine, that’s your cue to call the doctor.
Save this, share it, and use the flow chart when you need a clear next step.