I don't think there are any.... If so I need to talk to my doctor about what I can and can't do lol... I honestly think the only danger is if you are putting pressure on your tummy and it's causes pain.
No positions with you on your stomach obviously hahaha i don't think any are off limits? Me and my husband actually tried so many more positions while I was pregnant with our son and it had no harm of effect of our son.
That puts any pressure on you're tummy and you shouldn't be laying on your back for long periods of time. This is what my doctor told me.