Pregnancy Sleep – Is the Left Side the Best Side?

For years, women have been told that sleeping on the left side is the optimal position while pregnant. It's part of common pregnancy sleep folklore, but is it really true, or is it just an old wives' tale, like the one about moms with heartburn having babies with bushy heads of hair?

It turns out it is true that while you're pregnant, sleeping on your back is less than ideal. After about the 20th week of pregnancy, when you lie flat on your back, the weight of the fetus bearing down can put pressure on a major vein, the vena cava, that delivers blood to the heart. If there's pressure on the vena cava, blood flow to mom's heart slows down, which means that blood flow to the baby slows down, too. Not good.

So sleeping on your back is out, and sleeping on your stomach is out (for obvious reasons). But here's the secret: In order to prevent compressing the vena cava, you can pick either side to sleep on. It doesn't really matter, as long as you're comfortable. The more comfortable you are, the more likely you are to get healthy, restful sleep, and that's good for you and your baby.