@strawCake - It's so interesting that pregnancy can both cause and cure a tipped uterus. Glad thing worked out the right way with your friend's pregnancy!
I remember learning about this condition when I took anatomy and physiology quite awhile ago. Retrograde uterus is a fairly common condition among women, and as the article said, a lot of women don't know they have it!
It's also fairly common for other organs to be positioned backwards or on the wrong side of the body. And like the retrograde uterus, a lot of people don't realize their other organs are positioned differently than "normal."