As your pregnancy progresses, you might find sleeping more difficult. Your larger size makes it harder to get comfortable or you might wake up with unexplained twinges or spasms. Your sleeping position affects both you and your baby's health. While sleeping at a strange angle one night is unlikely to cause any health problems for your baby, prolonged sleeping on your front or right side can increase your risk of miscarriage.
Sleeping While Pregnant
Most doctors recommend sleeping on your left side when you're pregnant. Lying on your back cuts off blood supply by compressing the inferior vena cava. Strong circulation and blood supply help in the development of your fetus in the womb. While sleeping on your right side is unlikely to directly affect the baby, it can put added pressure on the liver. (See Ref 3) Any sleep positions that could cause you some harm or discomfort to you could eventually result in problems for the baby.
A June 2011 study published in the British Medical Journal found a small link between sleeping position and stillborn babies. Women who slept on their backs or on their right side had double the risk of having a stillborn child compared with women who slept on their left sides. However, the risks are still small -- at around four instances in every 1,000 people. Researchers also recommend further studies and don't claim this as conclusive proof. Nonetheless, the study backs up the medical suggestions to sleep on your left side wherever possible.
After the first trimester, you'll find it difficult to sleep on your stomach. Not only is it uncomfortable, it might be physically impossible as the weeks progress. As of July 2011, no scientific studies confirm the danger of sleeping on your front when pregnant. If you somehow manage to stay on your front, then you could risk damaging your child by putting additional pressure on her inside the womb. In serious cases, this could cause developmental problems or even miscarriage. However, this is rare as you're so unlikely to end up on your front.
If you struggle to get comfortable on your left side, try slipping a firm pillow between your knees. As well as improving blood flow, this position helps with kidney function and reducing swelling, according to the Children's Hospital of Pittsburgh. You'll find that during the latter stages of pregnancy, sleeping on your back puts too much pressure on your spine and stomach so you'll naturally want to sleep on your side.