well, I don't know--can't help but notice that adults are not babies, and have a far different body structure...
In the practise of dream yoga, (for example) you sleep on the right side, with the right arm lying along the bent leg, and the left palm under the head. The heart is not constricted this way.
Of course, most people will turn many times in a night. Best though, not to sleep on the left, and on the back, you snore, and/or get a very dry mouth.