Baby Fever Guide: When to Worry and What to Do
Fever is one of the symptoms that sends parents to Google at 2am more than almost any other. The key fact: fever is a symptom, not a disease, it is the body's healthy immune response to infection. The number on the thermometer matters less than how your baby looks and behaves.
⚠️ Under 3 months: any fever is an emergency
A temperature of 38°C or above in a baby under 3 months requires immediate medical attention. Do not manage at home. Call your GP, out-of-hours service, or take baby to A&E/Urgences/Notaufnahme. Newborns and young babies have immature immune systems, a serious bacterial infection can deteriorate very rapidly.
How to Measure Temperature Accurately
| Method | Age | Accuracy | Notes |
|---|---|---|---|
| Rectal (thermometer) | 0–2 years | Most accurate | Standard in FR/DE medical settings. 0.5°C higher than oral. |
| Axillary (armpit) | Any age | Good | Most common parent use. 0.5°C lower than rectal. |
| Temporal (forehead) | 3 months+ | Good for screening | Less accurate in very young babies. |
| Tympanic (ear) | 6 months+ | Good if done correctly | Ear canal must be clear. Often inaccurate in young babies. |
| Your hand | Any | Very poor | Cannot distinguish 37.5°C from 39°C, use a thermometer. |
Response by Age
| Age | Temperature | Action |
|---|---|---|
| Under 3 months | 38°C or above | Emergency, contact GP or A&E immediately |
| 3–6 months | 38°C–38.9°C | Monitor at home. Contact GP if persists over 24h or baby unwell. |
| 3–6 months | 39°C or above | Contact GP same day |
| 6 months+ | 38°C–39.5°C | Manage at home with paracetamol/ibuprofen. Contact GP if >48h or baby very unwell. |
| 6 months+ | Above 40°C | Contact GP same day, high fever always warrants assessment |
Managing Fever at Home
- Infant paracetamol (Calpol, Doliprane, Apiretal, Panadol Baby), suitable from 2 months (over 4kg). Dose is weight-based, check the packaging for your country's formulation. Never guess.
- Infant ibuprofen, suitable from 6 months. More effective for fever reduction than paracetamol as it reduces inflammation. Not suitable for babies with kidney/liver conditions or dehydration.
- Offer more feeds: Breastfed babies should be offered breast more frequently. Formula-fed babies should be offered extra cool boiled water between feeds.
- Keep baby cool but not cold: Remove extra layers. Light cotton clothing. Room temperature 16–20°C. Do not cover with heavy blankets.
- Do NOT use cold baths or tepid sponging, this causes shivering which raises core temperature. Not recommended by European paediatric guidelines.
Red Flags. Call Emergency Services (112/999)
Call immediately for any of these:
• Non-blanching rash (purple/red spots that don't disappear when pressed with a glass, possible meningitis sign)
• Seizure / convulsion, even if baby recovers quickly
• Stiff neck, sensitivity to light
• Difficulty breathing
• Unresponsive or very difficult to wake
• Extremely pale, blue-tinged, or mottled skin
• Bulging fontanelle (soft spot on top of head)