Why do babies smile in their sleep?

Shutterstock: st-fotograf

It surprises many parents to see their newborn baby smile as he sleeps a few days after coming home from the hospital. Even with the surprise that it causes, parents cannot deny the irresistibility of those cute little curled lips and happiness gleaming from baby’s face. But, what exactly causes baby to have these smiles? Is baby dreaming of the freshest diapers and tastiest bottles? Is baby happy that you are his mom?

It’d be nice if the baby could give us an answer as to why he has such a cute smile. It’d end all of the talks and wonder parents, doctors, and scientists all yearn to know. But, since talking is a skill that comes later in life, for now all we have to answer the question is educated and scientific guesses and doctor information. This information cannot tell us if a baby dreams, so perhaps it is sweet dreams that cause those adorable baby smiles.

Most babies smile as they enter the REM stage of sleep. This is the deep, restful sleep that adults wish they could get more of every night, so you can imagine how great it feels for your baby. The smile is done subconsciously without any effort from the baby. Although some doctors believe the smiles are caused by gas bubbles in the tummy, many others agree that it’s an unlikely cause. Parents can probably thank either of these two issues for those cute baby smiles.

Expect baby’s first ‘real’ smile at around two- six months of age. It’s this age when a baby begins to develop some emotional senses and responses and may react when to auditory stimuli, such as mom or dad’s voice. Later, the baby begins to respond to both auditory and visual stimuli. Soon, the baby will show off his smile often, with laughter following afterward. Once baby hones in on these skills there is no turning back and he’ll soon become your unstoppable bundle of joy.


So while there are several theories and possible reasons why baby smiles when he sleeps, it’s more likely than not that the smiles you see during the first few weeks of life are nothing more than twitches that happen as baby drifts off to rock-a-bye land. No matter what causes a baby to smile, there is no question that it’s perhaps one of the cutest photo-worthy moments in life.