A: Babies are notoriously noisy sleepers. They will grunt, moan, groan, and even wiggle in their sleep. We actually categorize sleep in babies as “active sleep” and “quiet sleep,” which coincides with REM sleep and non-REM sleep in children and adults. Furthermore, babies spend up to 50% of the night in this stage of active sleep. The only time to be concerned is if your baby snores or seems to have any difficulty breathing while asleep. If this is the case, be sure to talk to your healthcare provider at your next appointment.