Your baby seems off — not dramatically, just off — and you're stuck between watching a little longer and picking up the phone. First: you're not overreacting by wondering. Knowing the handful of symptoms that genuinely can't wait — and being allowed to act on a gut feeling — is one of the most useful things a parent can carry. This guide sorts the big red flags by how fast they need attention.

Go now — call an ambulance or head to emergency

Some signs mean help right away, not in the morning. Call 000 (AU), 911 (US), or your local emergency number — or go straight to your nearest emergency department — if your baby has any of these.

  • Trouble breathing — fast or laboured breaths, grunting with each breath, the skin sucking in between or under the ribs, long pauses, or blue/grey lips, tongue or face.
  • A baby you can't wake or who won't respond — floppy, limp, unusually drowsy, or staring and not engaging.
  • A rash that doesn't blanch — press a clear glass firmly against the spots; if they stay visible and don't fade, this can signal a serious infection. Don't wait to see if more appear.
  • A fit or seizure, repeated vomiting with a stiff neck, or a bulging soft spot.
  • A fever in a baby under 3 months. Any temperature of 38°C / 100.4°F or higher in a young baby needs urgent assessment — even if they otherwise seem fine.

Call today — your GP, child-health nurse, or after-hours line

These don't usually mean an ambulance, but they do mean speak to someone today rather than waiting and watching.

  • Signs of dehydration — far fewer wet nappies than usual, a dry mouth, no tears when crying, a sunken soft spot, or a baby who is listless and hard to rouse to feed.
  • Refusing feeds repeatedly, or vomiting everything back up over several feeds.
  • A fever in a baby 3–6 months, or a fever in an older baby that lasts more than two days or climbs despite simple measures.
  • Persistent diarrhoea or vomiting, especially with reduced wet nappies.
  • A baby who is much more unsettled or much quieter than their normal self.
Wet nappies (rough guide) What it usually means
6–8 heavy/day after the first week Well hydrated
Noticeably fewer than usual Watch closely, offer feeds, ring if it continues
Very few or none in 6–8+ hours Urgent — call today

Wet-nappy counts are a guide, not a diagnosis. Australia's Raising Children Network, the AAP (US) and WHO all point to the same core danger signs above — trouble breathing, poor feeding, lethargy, fever in a young baby — and the thresholds are broadly consistent across regions, though local advice lines (Healthdirect 1800 022 222 in AU; your pediatrician's nurse line in the US) differ in who you ring first.

Trust your gut

You don't need a textbook symptom to justify a call. Parents notice subtle changes — a different cry, an unusual stillness, a feeling that "this isn't right" — long before a number on a thermometer confirms it. Clinicians take parental instinct seriously, and so should you.

If in doubt about anything in this guide, your GP, child-health nurse, or local health line is always the right call — that's exactly what they're there for, at any hour.

This guide is general information, not medical advice, and can't diagnose your baby. When something worries you, contact your doctor, child-health nurse, or emergency services.