Polyps are areas that grow a little too much. As they grow, they usually fan out but remain attached to a small stalk, kind of similar to a bush or a tree. They are usually about the size of a pencil eraser, although they can be even smaller. Since most polyps are small, they probably do not often cause symptoms. However, when symptoms do occur, they usually include excessive bleeding during a menstrual period, or bleeding in between periods, or even spotting after intercourse.
Some women report a few days of brown blood after a normal menstrual period.
Polyps cause these symptoms because they dangle from their stalks and irritate the surrounding tissue, which causes the tissue to rub off, exposing tiny blood vessels. These blood vessels bleed, leading to spotting or vaginal bleeding. If the polyp interferes with the egg and sperm, it may make it hard to get pregnant. Nobody knows how common this is. It is also possible that they may lead to a slightly higher chance of miscarriage, but this is also unknown.