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.