When to worry about your baby’s temperature

Babies have an immature immune system in the first 3 months of life. This makes them particularly vulnerable to overwhelming infections. Just to keep things interesting, they also don’t tend to develop the typical high temperature we expect to see when children are unwell. A normal new-born temperature should range between 36.5C (97.8F) and 37C (98.8F). When unwell their temperature may go up or down just a tiny bit. Sometimes your baby may not show any other signs that they are unwell, but if your baby has a temperature outside the normal range they should definitely be reviewed, especially if they have any of the associated signs.

The most accurate way to take your baby’s temperature is using an armpit or rectal thermometer. If the result doesn’t seem accurate check on the alternate arm. Using an ear thermometer or forehead temperature strips are not accurate in small baby and not recommended. If you suspect the temperature is affected by clothing or the room temperature, adjust their clothing accordingly and recheck the temperature after 30 minutes.

If your baby has a temperature recording outside the normal range and/ or any of the concerns below please see a doctor:

  • Unusual skin colour: Pale mottled, blue lips, tongue or skin: discolouration may reflect changes in blood flow due to temperature fluctuations or dehydration.
  • No response to parental stimulation: not smiling to cues that they normally would, poor focus of eyes.
  • Sleepy: Does not wake up if roused or stay awake as long as usual
  • Unusual crying pattern: Weak cry, moaning or high pitched cry. Also continued irritable crying that does not stop with movements that would normally calm your baby down.
  • Difficulty breathing: rapid breathing, chest in drawing, grunting noise with breaths.
  • Bulging fontanelle: tense or protruding soft spot on their head.
  • Poor feeding: babies may have good and bad feeds, but if they take less than their usual amount on consecutive feeds they should definitely be reviewed.
  • Rash: a rash may be transient. Take a picture of your baby’s rash on your phone and arrange for a review. The picture may be useful in documenting how the rash has changed or spread over time.

After 3 months of age a baby may sometimes develop a high temperature and not be seriously unwell. These children will often have normal colouring, an easy to settle temperature, smiles, coos and responds to social cues, stay awake, have a normal consolable cry, moist mouth and eyes.  If they have any of these signs, it is important to arrange for a medical review:

  • Temperature above 39C
  • Temperature for 5 days or more
  • Child has a seizure
  • A rash that does not fade with pressure
  • Parents concerned that child has deteriorated since the last review


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