From third trimester onwards it's better to sleep on your side. You can try to fall asleep on your side, by morning usually you will roll back already which is fine
I was told that it disrupts the blood flow to the baby but it’s ok to lie on your back for a few mins i suppose - just not too long ◡̈
My gynae says better to slp on left side. As sleeping on the back will cause slower blood flow to baby
I was told that there is increase risk of stillborn if we were to sleep on our back
Its ok to sleep on your back as long you are comfortable