Few prenatal exercise questions create as much confusion as this one: Can you lie on your back during pregnancy?
You may have heard that lying on your back (or supine) is something to avoid after the first trimester, but the reality is more nuanced. The answer depends on what you’re doing, how long you’re there, and how your body responds.
This article breaks down what the research says about lying on your back during pregnancy — including how the guidance differs for sleeping, exercising, and modifying common supine movements — so that you can feel confident when making choices about your movements and activities.
Read on to learn:
- Where the concern about lying on your back during pregnancy originates from
- What the research says about sleeping on your back during pregnancy
- Whether exercising on your back is safe
- Simple modifications for common supine exercises
Quick Answer: Lying on your back during pregnancy is generally fine for short periods, but long durations — such as sleeping — can reduce blood flow to the fetus, particularly in the second and third trimesters. Side-lying is the recommended sleep position. For exercise, the periods on your back are brief enough that comfort is your best guide: if you experience dizziness, lightheadedness, or nausea, simply roll to your side. Most common supine exercises also have easy modifications if needed.
Where the Concern About Lying On Your Back Originates From
The concern with lying on your back during pregnancy is about blood flow.
In the second and third trimesters, the weight of the growing belly can compress major blood vessels when you are lying flat on your back. This can reduce blood and oxygen flow, and in some cases, lead to a condition called Supine Hypotensive Syndrome (SHS). Symptoms of SHS include dizziness, nausea, sweating, increased heart rate, and a reduction in blood pressure. These symptoms usually appear within 3-10 minutes of lying supine (4).
While SHS can sound concerning, the symptoms are usually temporary and resolve when you change position, such as rolling onto your side or propping yourself up at an incline. In other words, if you feel symptoms, there is no need to panic. Simply change position and let your body settle.
So, what does all this mean for things like sleeping and performing exercises on your back? Let’s look at each.
Is Sleeping on Your Back Safe During Pregnancy?
Research suggests that spending long periods lying flat on your back during later pregnancy may reduce uterine blood flow, which has been associated with fetal growth restriction and lower birth weight (1). Some studies have also linked going to sleep in a supine position after 28 weeks with an increased risk of late-term stillbirth (2).
That said, symptoms of Supine Hypotensive Syndrome are typically temporary and resolve with a change in position, such as rolling onto your side or propping yourself up at an incline (3).
In general, side-lying is the recommended sleep position during the second and third trimesters. Many experts recommend the left side because it may reduce pressure on the liver and support circulation to the heart, fetus, uterus, and kidneys. However, research comparing left- and right-side sleeping is inconclusive, and some experts suggest that blood flow is similar on both sides. So, see what feels most comfortable for you.
Is Exercising on Your Back During Pregnancy Safe?
Since longer periods in the supine position are not recommended in the second and third trimesters, it is natural to wonder whether supine exercises are safe.
Many international prenatal exercise guidelines recommend avoiding supine exercises after 16 weeks. However, a 2019 review by Mottola et al. notes that this recommendation was based primarily on expert opinion rather than clear scientific evidence (5).
Because the evidence is not definitive, our recommendation is to use your judgment and let comfort be your guide.
If you feel comfortable performing an exercise on your back, such as a chest press, bridge, or gentle stretch, it is generally fine to do so for short periods. If you begin to feel dizzy, lightheaded, nauseous, sweaty, or generally unwell, simply roll to your side and sit upright. The symptoms should resolve with the change in position.
Bottom Line: Being on your back for short periods of time to perform an exercise or gentle stretch is generally fine, provided you feel comfortable. If your body gives you signs that the position is not working for you, change position and choose a modification.
Modifications for Common Supine Exercises
The good news is that most supine exercises have simple alternatives if lying on your back feels uncomfortable. For each movement, start by identifying the goal of the exercise. Then choose another position or variation that accomplishes a similar purpose.
Here are a few examples with video demonstrations.
Floor Bridges
Bridges are an excellent exercise during pregnancy because strong glutes can help alleviate low back and pelvic pain. Standard bridges typically do not require a modification because you are on your back for a short period and actively moving. However, if lying flat feels uncomfortable, you can perform bridges with your shoulders elevated on a chair, couch, or bench.
Supine Chest Press
Instead of lying flat on your back, use an incline bench for your chest press. No bench available? You can also add a bridge to the movement. This keeps you moving while adding beneficial glute work.
Crunches and Leg Lifts
We recommend avoiding crunches and leg lifts once you develop a belly. This is not because they are performed on your back, but because they create excessive intra-abdominal pressure, which can exacerbate diastasis recti. Instead, movements like bird dog or an incline plank would be safer and more effective.
Savasana
Every yoga class ends with this wonderful relaxation, where you lie on your back for savasana. Even if you do not feel SHS symptoms from savasana, it may become increasingly uncomfortable as your pregnancy progresses. As an alternative, lie on your side, ideally with a blanket or pillow under your neck and between your legs to help keep your body in alignment.
We hope this helps clarify one of the more nuanced topics in prenatal exercise. Lying on your back during pregnancy is not an all-or-nothing rule. Context matters.
For sleeping, side-lying is generally the recommended position in the second and third trimesters. For exercise, short periods on your back are typically fine as long as you feel comfortable. And when lying flat no longer feels good, there are almost always simple, effective modifications available.
Resources
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Anderson, N.H., Gordon, A., Li, M., Cronin, R.S., Thompson, J.M.D., Raynes-Greenow, C.H., Heazell, A.E.P., Stacey, T., Culling, V.M., Wilson, J., Askie, L.M., Mitchell, E.A., McCowan, L.M.E. (2019). Association of Supine Going-to-Sleep Position in Late Pregnancy With Reduced Birth Weight: A Secondary Analysis of an Individual Participant Data Meta-analysis. JAMA Network Open, 2(10).
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Heazell, A., Li, M., Budd, J., Thompson, J., Stacey, T., Cronin, R.S., Martin, B., Roberts, D., Mitchell, E.A., McCowan, L. (2018). Association between maternal sleep practices and late stillbirth – findings from a stillbirth case-control study. BJOG, 125(2):254-262.
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Kim, D. R., & Wang, E. (2014). Prevention of supine hypotensive syndrome in pregnant women treated with transcranial magnetic stimulation. Psychiatry research, 218(1-2), 247–248.
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Kinsella, S.M. & Lohmann, G. (1994). Supine hypotensive syndrome. Obstetrics and Gynecology. 83:774–88.
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Mottola, M.F., Nagpal, T.S., Bgeginski, R., Davenport, M.H., Poitras, V.J., Gray, C.E., Davies, G.A., Adamo, K.B., Slater, L.G., Barrowman, N., Barakat, R., Ruchat, S. (2019). Is supine exercise associated with adverse maternal and fetal outcomes? A systematic review. British Journal of Sports Medicine 53:82-89.