Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services if your baby:
Breathing difficulty in a newborn always needs prompt medical assessment because it is not possible to identify the cause safely at home.
If your baby is still in hospital, tell a nurse or clinician immediately about fast breathing, grunting, unusual color, poor feeding, or increasing sleepiness.
Seek urgent medical care for persistent fast breathing, grunting, flared nostrils, skin pulling in around the ribs, feeding difficulty, repeated vomiting, or fewer wet diapers.
A fever or unusually low temperature in a newborn also needs urgent assessment.
Contact your baby’s healthcare team sooner if feeding, alertness, weight gain, or breathing does not seem to be progressing as expected.
After discharge, routine follow-up is usually through standard newborn visits.
Every sign above is quoted from the sofidex article on Transient tachypnea - newborn. If you are not sure, err upward — it is always reasonable to be checked.