It is fine to sleep however you are most comfortable. The only position truly discouraged is flat on your back due to suppression of a major artery.
Last time I slept any position where I was comfy. And everything was fine. This time I find I'm sleeping on my side and wake up on my stomach I'm 22 weeks and quite big already.
Left side is definitely always better but honestly I slept on my right side my entire pregnancy so far.only way I'm comfortable and so far so good and baby girl is soooo active
I sleep every single way. Even on my stomach. I haven't got big and didn't last time either.
I also can can sleep on my right side and my son was born within a 5 hour labour all natural
I Can Only Sleep On My Right Side & I Had No Trouble With My Delivery