Should you sleep on your back while pregnant?

During pregnancy, you may find yourself wrestling in bed trying to get comfortable before falling asleep. Unfortunately, your regular sleeping positions may no longer work for you during pregnancy — especially if you typically sleep on your back.

We normally advise patients to sleep on their side after 20 weeks of pregnancy. This is when a pregnant person’s belly really starts to expand.

When you lie belly-up, the weight of your uterus can put pressure on a major blood vessel, called the vena cava. This large vein runs up the right side of your spine and carries blood from the lower body to the heart. Compressing this can disrupt blood flow to your baby. Most people don’t experience this low blood pressure associated with sleeping on their back, so you can be reassured that if you wake up on your back, it’s unlikely to have ill effects to the baby. Those who do experience low blood pressure may have symptoms of nausea, dizziness and shortness of breath.

What about sleeping on your stomach?

Sleeping on your stomach is fine in early pregnancy, but sooner or later, you’ll have to turn over. Once your bump starts to show, stomach sleeping gets pretty uncomfortable in most pregnancies. If you need to sleep on your stomach, we recommend support pillows to offset your abdomen and hips, to avoid compression on the vena cava for the reasons mentioned above.

Switching up your sleep

Changing the way you sleep can be tricky, and it’s common to change positions during the night. As the stomach expands, sleeping on the back becomes more uncomfortable. Because of this, most people naturally shift to a different sleeping positions as pregnancy progresses. However, if you need help adjusting to side-sleeping, try slipping pillows between your knees and under your belly to make it more comfortable. If you still can’t comfortably make the switch to your side, use pillows to prop yourself into an incline, as sleeping on your back at a 45-degree tilt can prevent a lot of the compression.

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What if I wake up on my back or stomach?

Don’t stress out over occasionally rolling over onto your back at night or waking up on your back. Your body would let you know if your baby was in any real danger of not getting enough oxygen — you’d feel nauseated and breathless long before your baby would have a problem. If you continue to wake up on your back or stomach, ask your partner to check on you. If they wake up and notice you on your back, they can gently move you back to your left side.

More research needs to be done to determine any conclusive risks and, until then, it's best to follow the instructions of your doctor and organizations like the American Pregnancy Association and the American College of Obstetricians and Gynecologists.

Plus, you need your rest now more than ever — let's not give you one more thing to keep you up at night.