Help! 2 weeks old sleeping with mouth open

My 2 weeks old likes sleeping with mouth open. She is breathing well no snore or any discomfort but her mouth is always open when she is in deep sleep. Usually she will have her pacifier but when it drops or when we do not give she will sleep with mouth open. Is it common for newborn to sleep with mouth open? Based on her last pd visit doctor did not highlight any problems and she is not tongue tied as well.