Trust your body. This time round I'm a lot more comfortable on my back (or front!) than my side. My placenta's in the front and baby is usually transverse, I don't know if that makes a difference. My Dr and midwife have never, ever mentioned sleeping positions so I do think it is one of those things that has got blown out of proportion.
Im 38 weeks and only sleep on right side Dr said whatever is comfortable for you and baby.
I don't know exactly if it required sleeping on the left side during pregnancy but in my opinion, if you are not getting a perfect position to sleep then you should buy a pregnancy pillow that will help you to provide the perfect sleeping position with ease.
your body will let you know if your baby isn't getting enough oxygen because you'll feel kind of dizzy and nauseated when laying down on your back. it also depends on how the baby is positioned in your uterus. sometimes you can lay on your back and feel perfectly fine and sometimes it will make you feel yucky. it's probably not a big deal as long as you're comfortable.
Sleeping on your back may cut off blood circulation to your heart and the baby. Sleeping on either side is fine.
The reason they say sleep on the left side is bc the baby may not get as much oxygen sleeping on the back. It can pinch off the nerve and not allow as much oxygen to the baby a d the nerve is located on the left side.
No I'm 35 weeks I only sleep on my back and right side with both rarely on my left