How Long Can You Lay On Your Back When Pregnant? (OBGYN Explains)

Are you pregnant and wondering how long you can lay on your back?

In this post, you will learn:

What happens if you lay on your back for too long in pregnancy,
When you should stop lying on your back,
Safe sleeping positions during pregnancy, and more.

Let’s get started.

How Long Can You Lay On Your Back When Pregnant?

During the first and second trimesters, lying on your back for an extended period is generally safe.

However, as your pregnancy progresses into the third trimester, it is best to avoid laying flat on your back for more than a few minutes at a time.

What Happens If You Lay On Your Back For Too Long?

Lying on your back for too long during pregnancy can compress the inferior vena cava (IVC).

The IVC is a large vein that carries blood from the lower body to the heart.

As your baby grows, the weight of your uterus can compress the IVC and restrict blood flow to the baby.

Sadly, there is a lot of data that women who sleep on their backs during pregnancy have a higher rate of stillbirth after the third trimester. (Study 2) (Study 3).

Research also shows that there is an increase in blood circulation to the brain of babies whose mothers sleep on their backs. This redistribution of blood is a compensatory mechanism to ensure that the baby receives enough oxygen to the most vital organ (the brain).

When Should You Stop Lying On Your Back While Pregnant?

As OBGYNs, we recommend that you avoid laying on your back during pregnancy after 28 weeks of pregnancy.

With that said, a recent 2019 study showed no adverse effects of sleeping on your back up to the 30th week of pregnancy.

However, it is best to stop after 28 weeks to be on the safe side.

Can I Lay On My Back If Propped Up?

You can generally lay on your back while pregnant if you are propped up and not in a flat position.

The upright position will help take the pressure off your IVC and reduce the likelihood of compression.

What Is The Best Sleeping Position?

The best sleeping position during pregnancy is on your left side.

Sleeping on the left side allows maximum blood flow to the placenta and uterus.

Side sleeping is also best if you are experiencing lower back pain during pregnancy.

Can I Sleep On My Right Side During Pregnancy?

The National Institute for Health and Care Excellence (NICE) reviewed all available literature on sleeping positions during pregnancy in 2021. It concluded that sleeping on your right side during pregnancy is safe.

The only position associated with a higher risk of stillbirth is lying flat on your back.

What If I Wake Up On My Back?

If you wake up on your back while pregnant, there is likely no need to worry.

However, if you are constantly waking up on your back in the middle of the night, it might be beneficial to get a pregnancy pillow to help you stay on your side.

Placing a wedge pillow underneath your right side can also help keep you off your back at night.

Can I Lay On My Stomach In The First Trimester?

For most pregnant women, it is safe to sleep on your stomach in early pregnancy. (I was a stomach sleeper throughout the first trimester)!

However, as the pregnancy progresses and the baby grows, this position becomes more and more uncomfortable.

By the second trimester, most women find that sleeping on their stomachs is no longer possible.

Final Thoughts

In conclusion, lying on your back for too long during late pregnancy can compress a major blood vessel and reduce the flow of blood to your baby.

To reduce the stillbirth risk, we recommend that you avoid lying on your back after 28 weeks and prop yourself up if you must lie on your back.

It would be best if you also started sleeping on your side as soon as you enter the third trimester.

Now I want to hear from you.

What is the most comfortable sleeping position for you?

Can you get a good night’s sleep with your baby bump?

Comment below and let me know!

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Brittany Robles, MD, MPH, CPT

Brittany Robles is a full-time OBGYN physician, a NASM certified trainer, and a prenatal and postnatal fitness specialist. She holds a Master of Public Health degree in maternal health with a special interest in exercise and nutrition. She is also the co-author of The White Coat Trainer. Learn more about her here.

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References:

Heazell A, Li M, Budd J, Thompson J, Stacey T, Cronin RS, Martin B, Roberts D, Mitchell EA, McCowan L. Association between maternal sleep practices and late stillbirth – findings from a stillbirth case-control study. BJOG. 2018 Jan;125(2):254-262. DOI: 10.1111/1471-0528.14967. Epub 2017 Nov 20. PMID: 29152887; PMCID: PMC5765411.
Gordon A, Raynes-Greenow C, Bond D, Morris J, Rawlinson W, Jeffery H. Sleep position, fetal growth restriction, and late-pregnancy stillbirth: the Sydney stillbirth study. Obstet Gynecol. 2015 Feb;125(2):347-355. doi: 10.1097/AOG.0000000000000627. PMID: 25568999.
Stacey T, Thompson JM, Mitchell EA, Ekeroma AJ, Zuccollo JM, McCowan LM. Association between maternal sleep practices and risk of late stillbirth: a case-control study. BMJ. 2011 Jun 14;342:d3403. DOI: 10.1136/BMJ.d3403. PMID: 21673002; PMCID: PMC3114953.
Robertson N, Okano S, Kumar S. Sleep in the Supine Position during Pregnancy Is Associated with Fetal Cerebral Redistribution. J Clin Med. 2020 Jun 7;9(6):1773. doi: 10.3390/jcm9061773. PMID: 32517385; PMCID: PMC7356729.
Silver RM, Hunter S, Reddy UM, Facco F, Gibbins KJ, Grobman WA, Mercer BM, Haas DM, Simhan HN, Parry S, Wapner RJ, Louis J, Chung JM, Pien G, Schubert FP, Saade GR, Zee P, Redline S, Parker CB; Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (NuMoM2b) Study. Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes. Obstet Gynecol. 2019 Oct;134(4):667-676. doi: 10.1097/AOG.0000000000003458. PMID: 31503146; PMCID: PMC6768734.
National Guideline Alliance (UK). Maternal sleep position during pregnancy: Antenatal care: Evidence review W. London: National Institute for Health and Care Excellence (NICE); 2021 Aug. (NICE Guideline, No. 201.) Available from: https://www.ncbi.nlm.nih.gov/books/NBK573947/