Dehydration and fever in a newborn

A newborn may show dehydration through fewer wet nappies, a dry mouth, poor feeding, unusual sleepiness, weakness or a sunken soft spot. Fever can increase fluid loss, while infection can reduce feeding and urine output. Babies can look only mildly unwell despite a significant problem. Do not use thirst or urine colour alone to judge a newborn’s condition.

Measure the temperature with a reliable thermometer and note the reading, feeding pattern and wet nappies. Contact a healthcare professional urgently for advice rather than trying to manage suspected dehydration at home. Continue offering breast milk or usual formula if the baby is alert and able to feed, but do not dilute formula or give water unless a clinician specifically instructs you. Keep the baby comfortably dressed.

Seek emergency care immediately for a newborn with a fever, breathing difficulty, blue or grey colour, seizure, marked limpness, persistent vomiting, inability to feed, very few wet nappies or difficulty waking. Emergency assessment is also needed if the baby feels unusually cold or hot and is not behaving normally. Do not wait for dehydration signs to become obvious.

Tell the clinician the baby’s age, temperature method and reading, last feed, wet-nappy pattern, vomiting or diarrhoea, and any medicines already given.