Pretty sure its fine but once u get into ur 3rd trimester, space gets tight for baby in there and most doctors say you can interrupt normal blood flow/oxygen to ur baby if u lay flat on ur back for too long. So later on, what id do is make sure ur a little elevated do ur not completely flat. Thats how i slept with all of my pregnancies so far. Take care :)
When I sleep on my side my hips ache like crazy and I always have slept on my side. I used to get minor aches but this makes it so I can't sleep so I give up and lay on my back. I'm 12w5d.