Fever in babies under 1: when to monitor and when to seek help

What counts as a fever?

In babies and children, a fever is defined as a temperature of 38°C or above. The most reliable way to check this is with a digital thermometer, usually under the arm for younger babies.

Why do babies get fevers?

Fevers are most often linked to common viral infections such as colds or flu. They can also occur after vaccinations, which is a normal part of how the immune system responds.

In the majority of cases, a fever will settle on its own within a few days and does not require specific treatment. However, it can occasionally represent a serious bacterial infection which requires prompt action. Always take a baby <3 months to be assessed immediately by a medical practitioner.

How to care for a baby with a fever at home who is otherwise well

You can usually care for your baby at home if they are otherwise well.

• Offer regular feeds to keep them hydrated
• Keep them comfortably dressed, not too hot or cold
• Monitor their temperature and general behaviour
• Use infant paracetamol if advised by a healthcare professional

When to seek medical advice

It is always important to trust your instincts. You know your baby best, and if something does not feel right, it is appropriate to seek advice.

You should contact a healthcare professional if your baby is under 3 months and has a temperature of 38°C or above, or if they seem unusually drowsy, irritable, or difficult to wake. It is also important to seek advice if they are not feeding well, have fewer wet nappies than usual, or if their breathing appears rapid or laboured.

If the fever continues for more than a few days, or you have any concerns at all, it is always sensible to have your baby reviewed.

A calm and measured approach

Fevers can feel unsettling, particularly in the early months, but they are very common in the first year of life and are usually linked to minor illnesses.

Having clear guidance and understanding what to look out for can help you feel more confident in managing your baby at home, while also knowing when to seek support.

If you would like further reassurance, our team is here to help. Contact us to arrange an appointment.

For more information, the NHS also offers guidance on fever in children.