A normal menstrual period lasts from 2 to 7 days. The normal cycle patterns can range from 21 to 35 days. When bleeding occurs that is not part of the regular cycle; periods are longer or heavier than normal; occurs between periods; time between periods is longer than normal; or there is an absence of periods, this is called abnormal or irregular uterine bleeding. There are various causes of abnormal bleeding, but the most common is a hormone imbalance. At both ends of the menstrual life of a woman, periods may be irregular. Reasons for abnormal periods can be both normal and abnormal. The most normal reason is pregnancy. Hormone imbalance (not enough or too much of certain hormones) can also be a common reason. This can occur as a result of weight loss or gain; heavy exercise; stress; illness; or certain medications. The most common result of a hormone imbalance is loss of ovulation. If this occurs over a long period of time, a condition called endometrial hyperplasia can occur. Endometrial hyperplasia is the result of constant oestrogen bombardment of the endometrium (the lining of the uterus shed every month with your period). Untreated, endometrial hyperplasia (when the lining of the uterus becomes too thick) can sometimes turn into cancer.

There are many reasons for abnormal/irregular periods. The chart below will list the most common reasons, their cause, other symptoms that may occur, diagnostic methods and treatment options. Remember, this is not a replacement for the advice of your care giver, but rather information to help you become aware of your body.