How Long Can You Lie on Your Back When Pregnant?

There are all kinds of things you’re not supposed to do if you’re pregnant. You can’t drink, relax in a hot tub, have your morning coffee, enjoy delicious sushi, or even wear your favorite pair of stiletto heels. But did you know that there are even guidelines about how you sleep, particularly on how long you can lie on your back? 

You can lie on your back when pregnant up until the 20 week mark. Sleeping on your back after 20 weeks risks your baby’s development due to your uterus growing large enough to compress the inferior vena cava, which can restrict blood flow to your heart and may result in stillbirth.

While there’s no set number of hours determining when you should change positions, you shouldn’t sleep the entire night on your back. Lying on your back for a few hours, though, shouldn’t cause any problems.

Let’s dive a little deeper on when you should stop sleeping on your back during pregnancy, the reason you have to, and what you can do if you must lie on your back.

When Should I Stop Sleeping on My Back During Pregnancy?

The most dangerous time for women to sleep on their backs while pregnant is during their third trimesters (source: Obesity, Fitness & Wellness Week). However, the general rule is that you should stop sleeping on your back after 20 weeks.

It’s even better if you stop before that time, though, so that you can get used to your new sleeping position. 

Sleeping on your back could be dangerous for your developing baby because as your pregnancy develops, your uterus grows larger. By 20 weeks, it’s large enough that lying on your back causes it to sit on a large blood vessel called the inferior vena cava.

The weight of your uterus could compress the vena cava, restricting blood flow to your heart and, in turn, the growing fetus (source: Cleveland Clinic). 

This may cause stillbirths. Although many doctors insist further testing and research needs to occur to prove a conclusive link between back-sleeping and potential stillbirths.

Either way, it shouldn’t become a danger for most women until around 28 weeks, but it’s still safer to stop sleeping on your back, in the supine position, at 20 weeks or earlier.

pregnant woman sleeping on her back

I Can’t Stop Sleeping on My Back When Pregnant – What Can I Do?

The good news is in most cases, sleeping on your back doesn’t cause too many problems. In healthy women, the risk of vena cava compression is low, but in obese women, it’s a little higher (source: The Physiological Society). In either case, though, it’s still unlikely to cause you many problems.

According to Dr. Salena Zanotti of the Cleveland Clinic, your body knows what it needs and is going to let you know if something you’re doing is dangerous. “Your body is going to tell you something isn’t right, and that will make you move around,” she explains. 

She then goes on to say that you’ll experience noticeable symptoms long before lying on your back has time to do any damage to your baby. These symptoms include:

  • Dizziness
  • Shortness of breath
  • Increased heartbeat

Dr. Zanotti also notes that most pregnant women wake up at least a few times a night for bathroom breaks, making it even more unlikely that they’ll sleep on their backs long enough to cause any harm (source: Cleveland Clinic).

In other words, if you wake up in the middle of the night and realize you’ve been sleeping on your back, don’t panic. The anxiety and alarm you experience will be far worse for your baby than those few hours on your back. If you’re feeling super anxious about it, though, there are some things you can do to help you stay off your back.

Become a Side Sleeper

You should learn to become a left- or right-side sleeper. That’ll solve most of your problems and keep you from worrying unnecessarily. However, for some people, that’s easier said than done. 

If you’ve been trying and failing to sleep on your side but aren’t finding it comfortable, try putting a pillow between your knees and another behind your hips. This helps some women feel more balanced and comfortable.

You can also try sleeping with a full-body pillow behind you to keep you on your side. If you’re a cuddler, you can even have your partner sleep close behind you to keep you from rolling over onto your back at night.

Sleeping on your side has other benefits, as well, such as reducing back problems and the risk of varicose veins and hemorrhoids (source: American Pregnancy Association).

Put a Pillow Under Your Back

The problem with sleeping on your back comes mainly from sleeping flat on your back. If you can’t keep yourself off your back, then put a thick pillow under it. The pillow will elevate your back and put you sleeping at a slight angle. Even that small 20% angle should be enough to keep you safe from vena cava compression. 

Buy a Firmer Mattress

Some women don’t like sleeping on their sides when pregnant because their bellies’ weight makes their back hurt. You can mitigate this pressure by investing in a firmer mattress for extra support. Gel-memory foam is an excellent option due to the softness of the mattress and the cooling properties provided by the gel.

Invest in a Pregnancy Pillow

Pregnancy pillows are specifically designed to cradle your belly, support your spine, and keep you from rolling over onto your back while sleeping. Some are ‘C’-shaped, while others are ‘U’-shaped.

‘C’-shaped pillows like this INSEN Pregnancy Pillow are preferable because they provide more comprehensive support. They also seem to do a better job of keeping you off your back.

INSEN Pregnancy Pillow, Maternity Body Pillow for Pregnant Women,C Shaped Pillow with Jersey Body Pillow Cover

As your pregnancy progresses, it may become harder to use a pregnancy pillow. At this point, you can try using wedge pillows. Strategically place them so that they keep you at an angle, off your back, and comfortable (source: Healthline).

Can I Sleep at an Angle/Propped Up When Pregnant?

It’s safe to sleep propped up while pregnant. Remember, Dr. Zanotti mentioned that sleeping even at a 20-degree angle would be enough to help combat any adverse effects that might stem from back-sleeping. 

woman sleeping propped up while pregnant

Not only is propping yourself up safe, but it’s also an excellent way to combat heartburn and acid reflux while pregnant. If you want to be extra safe, you can still sleep on your side. Just use strategically placed wedge-shaped pillows to keep the top half of your body elevated while sleeping.

You can even place books or boards under the head of your bed to elevate it, although that might cause your partner some distress. WebMD suggests using four- to six-inch boards for optimal elevation (source: WebMD).

How Far Can You Recline When You’re Pregnant?

Reclining while pregnant is fine as long as you’re at an angle. In fact, many women find that they sleep better in recliners than the bed. As long as the recliner isn’t keeping you in a flat-on-your-back position, it’s a perfectly safe alternative to sleeping in a bed. 

A quick Google search may scare you away from sleeping in recliners. There are all kinds of forum conversations and “mommy blog” posts insisting that sleeping in a recliner after 30 weeks is dangerous and will cause your baby to move into the posterior position, which makes delivery harder.

No scientific evidence has been found that supports this. Experts say that reclining, whether it’s in a recliner or by using wedge pillows on the couch, is perfectly safe for your baby. 

Keep at a 45-degree angle or higher, and don’t stay in any one position for too long unless ordered to bed rest by your doctor. Except for those particular cases, standing, moving around, and changing positions occasionally is always preferable to sitting and lying in a single position for hours on end.