A childhood belief about reproduction

This isn't really a belief, or at least I only believed it for an hour or so, but I'm adding it anyway because mothers may appreciate it. In 8th grade sex ed, the teacher had one of those cross-section pictures, as if you sliced someone right down the middle, and this one was of a pregnant woman at full term. In this cross-section picture, the urethra and rectum appeared to be squashed completely flat, and the bladder was significantly flattened too. So at the end of class I went up to the teacher and asked, "everything isn't really flattened like that, is it? it just looks that way from the way the picture is made?" My teacher -- who had a couple of kids -- laughed and explained that no, everything really is squished like that and that she had to go to the bathroom like every half hour near the end of her pregnancy (an experience I know is shared by many moms). This did not exactly make me want to have kids.