so if you are not having problems sleeping on your back. it is fine and does not put any risk to the fetus. . your body will tell you when you cannot be on your back anymore. the reason many physicians tell you not to sleep on your back is due to the uterus' pressure on the inferior vena cava (a large blood vessel that takes blood back to the heart from the lower body). this decreases the blood flow back to the heart which causes all of the changes for patients. it causes a decrease in the blood flow to the heart and causes the mother to sweat increase in heart rate and nervous. the mother will need to get off of [her] back to feel better.
is it dangerous to sleep on your back when you are pregnant?