Has anyone been advised by their medical carer to avoid sleeping on their back when 20 weeks plus pregnant? My OB didn't and when I asked him about it, he said it's fine unless I suffer from dizzy spells. I am sleeping on my sides just to be safe. I 'm afraid baby will not get enough oxygen or nutrients if a blood vessel is restricted? I normally sleep on my back so it's been a conscious effort to do so and not very comfortable either. What have you been told and what are your thoughts or experience on this matter?