Sleeping while pregnant can pose quite the challenge. During the second trimester of my pregnancy, I learned that I had to start considering changing my sleeping position to make sure my baby’s health wasn’t being put at risk. As you can imagine, this made me so paranoid and worried about my sleeping habits that it even disrupted my ability to sleep throughout the night. I decided to consult with experts to find out if there was any truth to the information I was reading online. After all, everyone’s pregnancy is different and by this point I’d already been sleeping with a pregnancy pillow to keep me comfortable and supported throughout the night. 

During the third trimester I officially found myself switching the way I slept to not only protect my baby, but so I could be more comfortable as well. Let’s just say my go-to sleeping position (on my stomach) was out of the question. If you’re newly pregnant and have been wondering about this pressing topic, here’s what some OB-GYNs had to say about the best sleeping positions during pregnancy. 

Why you need to change your sleep position during pregnancy

It’s important to understand why and how your sleeping position can affect your unborn baby. This is generally more relevant during the second trimester and onwards. 

Doctors advise that you avoid sleeping flat on your back (or stomach), because your growing uterus can compress the vena cava. The vena cava is a large vein that is made up of the superior and inferior vena cava veins, which are responsible for carrying deoxygenated blood to your heart from your lower and upper body. In this case, the one you have to worry about constricting is the inferior vena cava, which is the largest vein that carries blood from your lower body up to the heart.

“If the vena cava is compressed, there will be less blood returning to the heart from the legs, so cardiac output drops and blood pressure drops,” said Dr. Alan Peaceman, chief of maternal fetal medicine in the Department of Obstetrics and Gynecology at Northwestern University Feinberg School of Medicine. “The blood flow to the uterus will decrease and the baby may not get enough oxygen,” he warned. 

Dr. Nisarg Patel, an obstetrician at Clinicspots added that if the vena cava is constantly compressed, this can lead to low birth weight, stillbirth, preeclampsia or gestational diabetes. It can also increase the chances of a cesarean section.

However, there’s no need to worry if you’re early on in your second trimester and still find it more comfortable to sleep on your back or stomach. “The uterus does not even reach the vena cava until after 20 weeks of pregnancy and cannot compress it until sometime in the third trimester,” clarified Dr. Peaceman. 

To be more specific, it’s crucial that by the time you approach 28 weeks (the official start of the third trimester), you should be changing up the way you sleep. In fact, if your uterus happens to be compressing the vena cava, you would know because you’d experience symptoms like dizziness and shortness of breath, since there would be decreased cardiac output. “The pregnant person’s brain will also be receiving less blood and experience lower blood pressure so when this happens, they will feel short of breath and instinctively roll over until their blood pressure and perfusion are back to normal,” said Dr. Peaceman. 

The recommended sleeping positions

Now that you know that sleeping on your back and stomach is not the best option after a certain point during your pregnancy, it’s helpful to know the positions that are approved to get a good night’s sleep. Sleeping on your left side is considered the most ideal because it allows for proper blood flow from the vena cava. Since blood flow is most optimal in this position, it will keep any hand, ankle and feet swelling at bay. It also takes pressure off your kidneys and liver. 

“To make this position more comfortable, you can use pillows to support your back, belly, and legs, and you can also bend your knees and put a pillow between them to reduce the strain on your hips and lower back,” suggested Dr. Patel.

Sleeping on your right side is also acceptable. A 2021 study looked at the possibility of stillbirth or having a baby small for gestational age based on sleeping positions and found no association when the pregnant individual slept on their left or right side. On the other hand, there was evidence that pregnant people who slept on their backs after 28 weeks of pregnancy doubled their odds of stillbirth or having babies born small for gestational age. 

Dr. Peaceman advises that even rolling as little as 15 degrees to one side or the other is enough to get the uterus off the vena cava.

How to make side sleeping more comfortable

If you aren’t normally a side sleeper and are trying to find ways to make it more comfortable, using a pregnancy pillow for support around your back and belly can make it more bearable. Before I was pregnant I’d alternate between sleeping on my right side or my stomach. 

Now that I’m in my third trimester I take turns sleeping on my right and left side and it took some getting used to. I was never a left side sleeper, so using a full body pregnancy pillow like the Momcozy Maternity Body Pillow and a wedge pillow like the Hiccapop Pregnancy Pillow Wedge was a game changer. I use the wedge pillow to support my growing belly and the body pillow to help keep me in position and from rolling onto my back. I also like my head more elevated as I sleep, so I top it off with a regular pillow and it completes the cocoon-like feel in my sleep pod.

But if you do find yourself waking up in the supine position on some mornings or after a nap (I know I have), there’s no need to panic. “Occasional back or stomach sleeping is unlikely to harm your baby, as long as you change your position as soon as you realize it,” explained Dr. Patel. The only time it’s concerning is if you spend long periods in this position, especially during the third trimester since it can increase the risk of complications. 

If you still find yourself struggling to stay asleep on your left or right side, Dr. David Caiseda, medical director and obstetrician at the University of Maryland Charles Regional Medical Center, suggests to “try and sleep in a reclining chair for extra comfort.”

Takeaway

Pregnancy is hard as is — the last thing you need to worry about is if you’re sleeping correctly. Luckily, there are ways around it and props like pregnancy pillows to help improve the experience. As always if you have any questions during your pregnancy about the safest ways to sleep or the well-being of your unborn child, make sure to discuss these matters with your doctor first.

The Best Pregnancy Pillows, as Tested By a Pregnant Wellness Editor See at Cnet