I find this one very interesting because it makes me wonder if thousands of years ago our ancestors worried about this? Probably not but they also didn’t live much past 20 so I’ll press on.
You have a large vein (called the inferior vena cava) that carries blood back to the heart from your feet and legs and your largest artery (called your aorta) running down your body so if you’re giant pregnant and your uterus presses on them for any great length of time you could compress them. If this happens then a crazy thing occurs, you become uncomfortable, possibly dizzy and breathless and, you know what, you move. Plus, you rarely stay in the same position when you sleep so whether you’re trying to stay on or off your back, you’re not going to be successful doing either for very long.
What I found interesting is if you pose the question about sleeping positions, the party line is to stay off your back and ideally sleep on your left side to maximize blood flow, etc. but if you’re complaining about not being able to get comfortable when you sleep, all this flies out the window and it’s whatever works. This includes sleeping on your stomach if you’re still physically able to do it.
I was pretty impressed with the level of know how the human body is equipped with so, unless you have some kind of underlying health issue like high blood pressure, preeclampsia, preterm labor or placental insufficiency, it looks like you should sleep and rest in whatever position is the most comfortable. After all if peeing, heartburn, baby kicking, leg cramps, constipation or the general panic of becoming a mother isn’t keeping you up, Honey, get your rest.
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