Bleeding gums is a sign of gum disease.
Gingivitis is the inflammation of the gums and is usually caused by bacteria. If left untreated it can become a more serious condition known as periodontitis. There are several risk factors for gum disease which include diabetes and pregnancy. It is possible to have gum disease and not be aware.
Some of the symptoms include:
Red, tender or swollen gums
Bleeding when you brush or floss
Gums receded from your teeth