It may be normal for newborns to sleep with their tongues out, but it can also be caused by abnormalities, such as indigestion and Down’s syndrome. 1. Normal phenomenon: The salivary glands of newborns begin to develop, the amount of saliva secreted will be more, so it is easier to spit out the tongue when sleeping, which is a normal phenomenon, usually do not need to worry too much. 2. Abnormalities: (1) indigestion: if parents do not feed properly and give newborn babies too much to eat, it may lead to indigestion, and the baby may be uncomfortable and will have the phenomenon of spitting out the tongue when sleeping. (2) Down syndrome: Down syndrome is related to chromosomal abnormality, which is mainly manifested as growth retardation, peculiar facial features, backward intelligence, etc. The baby may also be accompanied by symptoms such as opening the mouth and sticking out the tongue and drooling too much. Newborns sleep tongue, if there are other abnormal symptoms, it is recommended to actively go to the regular hospital, a clear diagnosis, follow the doctor’s instructions for treatment, so as not to delay the condition.