Is it safe to sleep on my back when pregnant?

1In pregnancy, it seems like women become magnets for comments, scary birth stories and well meaning, but often incorrect advice.  I have lost count of the number of clients that begin their appointment feeing anxious because their co-worker or cousin or the checkout person at the grocery store have created panic by sharing their expert opinions. I’m guessing that the question, “Is it safe to sleep on my back when pregnant,” has come up because of well-meaning advice.

I once had a lovely first time Momma, still early in her pregnancy come into my office in a bit of a panic.   As is my usual custom, I first asked her if there was anything she wanted to talk about.  She immediately told me how worried she had been because she had been sleeping on her back, and a friend had told her that her baby would die if she slept on her back.   Before I go any further, let me reassure you, her baby is just fine.  But this is definitely a concern that we encounter frequently and is worth exploring.

woman-1118212_1280 copyIs it okay to sleep on your back?  Yes and no.   In the first trimester, the baby is pretty small and likely will not have any effect on your circulation.  But as you enter your second trimester, your growing baby/uterus can place more pressure on the vena cava (the vein that brings deoxygenated blood back to the heart to be re-oxygenated and sent back our from the heart to be delivered to all the tissues in your body). If your baby/uterus is compressing this vein, then there will be a delay in the venous blood return.

Is this dangerous?

Theoretically, however, it would affect you first before affecting the baby. You will feel unwell long before the baby is impacted. If your blood flow is being affected, you will feel uncomfortable and you either wake up or change positions. Worried that you are a deep sleeper and won’t notice? When was the last time you wet the bed because you slept through the sensations of a full bladder? Precisely.

Lying flat on your back is usually only a concern if you are medicated or unable to move. The perfect example is when one has an epidural. You can’t feel the cues that indicate a problem and you can’t easily shift position even if you wanted to. We will always put  a rolled up towel or other wedge your hip when you have an epidural to tip you (and the weight of your uterus) slightly to the side. Problem solved.

So yes, you can put a pillow or rolled up blanket under your right hip to reduce the pressure on your vein to avoid sleeping on your back.  But if you wake up in the middle of the night and you are on your back, don’t worry.  Your body is smart. Even when you are sleeping you are doing your best to protect yourself and your baby. You likely woke up because your uterus was compressing your vein and your body knew you needed to change positions.  Either that or your baby was compressing your bladder and you need to get up and pee for the 17th time, and sadly, no pillow under you hip will help with that!


Leah Hackett is a registered midwife with Generations Midwifery Care. Learn more about Leah here.