stomach is sometimes called the prone position.
Some people naturally prefer this position, and it may reduce snoring for certain individuals because the airway can remain more open than when lying on the back.
However, stomach sleeping has a potential disadvantage: the head usually has to remain turned to one side in order to breathe.
This can place strain on the neck.
It may also increase pressure on the lower back if the body is not properly supported.
For these reasons, stomach sleeping is generally not considered the best position