Baby Fever: When to Worry and What to Do — Pediatrician-Backed Guide

Your baby feels warm. You check the thermometer. It reads 38.3°C (101°F).

Is it dangerous? Should you rush to the hospital? Or wait and watch?

Here’s the clear, medical truth — no guessing, no panic.

What Is a Fever in Babies?

• Fever = Rectal temperature ≥ 38.0°C (100.4°F)

• It's the body’s natural response to infection.

When to Worry Based on Age

🍼 Age 0–3 Months

• Call your doctor immediately if rectal temp is ≥ 38.0°C (100.4°F)

• Fever in this age = possible serious infection (even without other symptoms)

👶 Age 3–6 Months

• Monitor behavior, hydration, feeding

• See a doctor if fever is ≥ 39.0°C (102.2°F) or baby is irritable, lethargic, or not feeding

👧 Age > 6 Months

• Evaluate overall condition: active vs. limp, drinking fluids, responding to you

• Watch for red flags below

Red Flags — Go to ER If You See:

• Difficulty breathing

• Baby is unresponsive or very drowsy

• Stiff neck

• Seizure

• Rash that doesn’t fade with pressure

• Signs of dehydration (no tears, dry mouth, no wet diapers > 8 hours)

• Bulging fontanel (soft spot)