Newborns can be surprisingly loud and noisy when they slumber, but this is another quirk that is typically normal and nothing to worry about. As your baby's nervous system matures and reflexes fade, you'll likely notice that they grow into much quieter sleep by about 5 months.
One of the main culprits for noisy newborn sleep is their tiny noses and airways. As they breathe, you might hear snorts, grunts, whimpers, and even rattling sounds typical of mucous – all in the normal range of expected sleep sounds.
Noisy newborn sleep and any feeding challenges should be mentioned to your pediatrician. Be on the lookout for these sounds, which are not considered normal and may indicate difficulty breathing.
Rapid, strained, persistent grunting after each breath
Pauses or gasps between breathing
Wheezing can sound like whistling coming from their chest and may be visually accompanied by retractions. Retractions can be identified by seeing if their chest pulls in with each breath around their rib cage or collarbone.
A high-pitched cough, sometimes compared to a "barking seal." This is a signature sound of croup, a response to any number of respiratory viruses where their tiny airways start to swell.
Call your pediatrician or seek medical attention immediately if signs of respiratory distress accompany your baby's noises.