What Happens When You Lie On Your Back In Pregnancy

Most expecting women have heard the warning “you can’t sleep on your back in pregnancy”. It’s one of the reasons why pregnancy body pillows are so popular because they are designed to support your joints and keep you in a comfortable side-lying position. That recommendation stems from it being best for women to avoid lying on their back for extended periods of time — whether that’s while sleeping, doing daily activities, or while exercising.

Is it really that dangerous to lie on your back during pregnancy?

Avoiding supine positions for an extended period of time is an important prenatal modification to follow. But that doesn’t mean lying on your back for brief periods of time will cause direct harm to you and your baby. That’s why it’s just as important to know why you should avoid lying on your back, and what the guidance actually suggests.

What to know about lying on your back in pregnancy

A lot of prenatal guidance comes in broad generalizations, such as “don’t lie on your back” or “don’t raise your arms over your head” or “don’t over-exert yourself”. But the rigidity and lack of reasoning behind this guidance can lead to more fear and confusion in the long run, and that’s what we want to dispel!

Here is the truth about lying on your back in pregnancy:

In the second half of your pregnancy (after about 18-20 weeks), the weight of the baby, amniotic fluid, placenta, and uterus have significantly increased. When lying on your back, that added weight can put pressure on your inferior vena cava, a major vein leading back to your heart. That has the potential to partially disrupt blood flow, and that’s why it’s advised to avoid lying on your back for extended periods of time.

What will happen if I lie on my back while pregnant?

You probably won’t notice anything right away. The first sign that you should change positions as soon as possible is a feeling of being light-headed or dizzy. This is a sign that your position may be restricting natural blood flow.

What should I do if I start feeling dizzy?

It’s best to change your positions right away but do so in a slow and controlled manner. All you have to do is roll over to your left side and wait for any dizziness to pass, then gradually sit up. It won’t harm you or your baby otherwise! 

What happens if I roll over onto my back in my sleep? 

The best guidance is to create a sleep situation where you feel comfortable and supported sleeping on your side. Again, pregnancy pillows can help with this! But if you do end up rolling over onto your back while sleeping, try not to stress too much. Many doctors agree that ending up on your back here and there throughout the night should not be harmful to your baby.

If you find yourself most comfortable on your back while sleeping, you can try a semi-reclined setup using a wedge pillow. This will keep you up at an incline that should mitigate the weight of your bump pressing against your vena cava. It will also make it easier to breathe and can reduce heartburn and acid reflux symptoms.

Does the fear of lying on your back prevent you from doing other activities?

One of the number one misconceptions we hear about prenatal exercise has to do with reclined or semi-reclined positions. We find that some women choose to avoid exercise, even when it’s designed to be pregnancy-safe because a position might feel like you are lying on your back too much. So we want to explain what workouts are actually safe and which reclined exercises you should definitely avoid.

Reclined and semi-reclined workouts that are considered safe in pregnancy:

You will see a few stretches and cool-down moves in the Fitness Studio that may have you on your back, but for a very short amount of time (less than 1 minute!). This is not long enough to cause any dizziness or harm to you or your baby. These stretches can help you release tough to target lower back tension and glute tightness.

As you progress later in your pregnancy you will see glute bridge exercises featured in the app as well. Keep in mind that in this position your hips should be lifted (you’re working those glutes after all)! Since your lower back is off the floor, there is no direct pressure on your back, so the weight of gravity won’t have the same compression effect on those blood vessels. The bridge is actually a great exercise as you move later into pregnancy as it helps strengthen your butt and hips to prepare for labor.

Similarly, moves like elevated bridges, reverse tabletops where your back is not pressing directly on the ground should be safe throughout your pregnancy.

Reclined workouts that you should definitely avoid in pregnancy:

Once you’re in your 2nd or 3rd trimester we absolutely advise against workouts that place added pressure on your back. This could be things like reclined leg press-ups or bench presses. Additionally, if any particular move (reclined or not) causes you to feel lightheaded or dizzy, please avoid it. If you do ever feel dizzy working out, you know what to do: stop right away, roll over onto your left side, and slowly sit up.

I still don’t feel comfortable being on my back at all, what should I do?

If anything makes you feel uncomfortable during your pregnancy, please listen to your body and your intuition. Skip any workouts that don’t feel right to you, cause pain, or leave you feeling unsafe in any way. Our team of experts is here to help you know what’s safe in pregnancy and beyond — but your body is your best resource at the end of the day. Tune in to what it tells you.

Do you have any questions about exercise safety or lying on your back in pregnancy? Leave them in the comments below and we’ll answer in a future post!

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