My doctor told me I could lay on my belly all the way up until I was giving birth as long as I am comfortable. He said, "I don't know how the heck you're comfortable on your tummy at 30 weeks, but go for it!". He said the only "bad" position is on your back.

Lay on your belly for as long as you feel comfortable

actually you can lay on your stomach as long as your comfortable.

ohhh okayyy thankss @sierraannmariee

You can lay on your stomach until your 20 weeks