Since I just found out I am pregnant I have done A LOT of reading. All the books say the best sleeping position is on your left side. I know that you should sleep on your side when you are farther along in pregnancy, but why your left side? Can you sleep on your right side? Does it really matter which side?

It helps the blood flow and circulation of oxygen and nutrients or something. My doctor always told me that. I sleep on my stomach until I can't anymore, then I move to my side. It is hard to train your body to sleep in a new position. I suggest getting yourself one of those body pillows that looks like a big horseshoe, it will help train your body (and thy are comfy too)

Most physicians recommend that a woman sleep on her left side while pregnant. This allows for the maximum blood flow to the baby, and it will also improve kidney function for the mother. The improved kidney flow will help to reduce swelling. Because your liver is on the right side of your body, sleeping on your left will keep the pressure off your liver.

Early in pregnancy, you should attempt to get into the habit of side sleeping. Typically the most comfortable position is with your knees bent. You may wish to place a pillow between your knees to sleep more comfortably.

The best sleeping position for a pregnant woman is on her side, especially the left side, because it allows for maximum blood flow to the fetus and improves kidney function in the mother. Improved kidney flow helps to reduce any swelling. Placing a pillow between the knees can help a pregnant woman sleep more comfortably on her side. Also, using a bunched-up pillow or rolled-up blanket at the small of your back may help to relieve some pressure.

That's why J_9 is so good at her job. :) this is an example of the pillow I use, I love it.
http://www.prenatalcomforts.com/files/SnoogleAndCover/snooglebodypillow.gif

Girl, I have a 9 mnth old baby. Let me tell you, sleep however you want while you can! Soon you won't be able to sleep on you belly because its too big, then you can't sleep on your back cause of the weight on something, don't remember, then you'll only be able to sleep on your sides! If your blood pressure gets high, you'll have to lay on your left side. So I say lay every way except your left side while you can!! Lol

Lol... I used one in between pregnancies...