Fever in babies: how to measure, when to worry and what to do

How to measure a baby's temperature

Use a digital thermometer. For babies, a rectal temperature is the most reliable in the first months, according to Norwegian health advice. In older babies, an ear or armpit thermometer can be used, though armpit readings are less exact. Follow the thermometer's instructions and clean it after each use.

Fever is generally defined as a temperature of 38.0 degrees Celsius or higher. Do not judge a fever by touching the forehead alone, and remember that overdressing or a hot room can raise the reading a little.

Babies under 3 months: act quickly

For a baby under 3 months, a temperature of 38.0 or higher is always a reason to contact a doctor the same day, including at night. Call your GP, or the out-of-hours service (legevakt) on 116 117, and call 113 if your baby seems very unwell.

Young babies can become seriously ill quickly and may have few other symptoms, so do not wait to see if it passes. A very low temperature in a young baby that does not rise when warmed can also be a sign of illness.

Older babies: look at the whole child

For babies over 3 months, how your baby behaves tells you more than the number. A baby who feeds, plays and is alert between spells of fever is generally less worrying than one who is limp, hard to wake or inconsolable.

Contact a doctor if the fever lasts more than about 3 days, if your baby is 3 to 6 months and has a temperature of 39 or above, or if you are worried for any reason. Trust your instincts.

Warning signs: seek help straight away

Call 113 or go to the emergency room if your baby has difficulty breathing or breathes fast with effort, has a rash that does not fade when you press a glass against it, a stiff neck, a bulging soft spot, a seizure, blue or very pale skin, is very drowsy or floppy, or has a high-pitched or weak cry.

Also seek help for signs of dehydration: no wet nappy for 6 to 8 hours or more, dry mouth, sunken soft spot, no tears, or refusing all fluids.

How to comfort a baby with fever

Offer extra fluids: breast milk or formula as often as your baby wants. Dress your baby in light clothing and keep the room comfortably cool, not cold. Do not wrap a feverish baby in extra blankets, and do not use cold baths or alcohol rubs.

Pain and fever medicines can be considered for older babies who are uncomfortable, but ask a doctor, health nurse or pharmacist about what is suitable for your baby's age and weight. Never give a baby medicine without advice, and never aspirin.

Fever after vaccination

A mild fever can occur in the day or two after a vaccine. The child vaccination programme leaflet from the health clinic explains what to expect. If the fever is high, lasts longer than expected, or your baby seems unwell, contact your health clinic or doctor.