All the pregnancy books say that once you're about half-way through your pregnancy, you should never never never lie on your back. Something about a vein that takes blood/oxygen to the placenta getting squished, so it isn't good for the baby. So, I have dutifully attempted to stop sleeping on my back, which is no small feat when that's the way you've slept for most of your life.
Until tonight, when I realized something.
As soon as you go to the hospital to labor and deliver the baby, they make you lie on your back. For hours.
Logically: It can't be both awful to lie on your back during pregnancy and essential to lie on your back during labor.
It's a conspiracy, I tell you.