During pregnancy you might find yourself tossing back and forth at night to find a comfortable spot. You may have to change your usual sleeping positions for your second and third trimester. Sleeping directly on your back after 20 weeks should be avoided. This is because a large vein, called the vena cava, delivers blood from your lower back to your heart. If you lie flat on your back and the baby is on the right side, it could compress the vein and could block delivery of blood back to your heart.
I recommend sleeping on your side, preferably your left side to prevent this from happening. Sleeping on your left side increases the amount of blood and nutrients that reach the placenta and the baby. You can try sleeping on your stomach if you usually sleep that way, but when you are farther along in your pregnancy it may be difficult because of the physical changes you are undergoing.
Don’t be alarmed if you go to sleep and wake up lying on your back. It will happen from time to time and it shouldn’t have a serious affect on your baby’s health. Just move to your side and go back to sleep.
Buying a maternity pillow might be helpful. There are many varieties you can choose from. Check online options for styles and sizes.