As you get closer to menopause, menstrual cycles change in several ways.Cycles that used to be 28-30 days occur at closer intervals, often 21-28 days. Many women notice that the flow may change. Bleeding can seem heavier for the first two days of the cycle, then flow can become lighter, and there can be several days of spotting at the end of the cycle. It is not abnormal if the total cycle lasts 7-8 days, with spotting at the beginning and end. As one gets even closer to menopause, cycles become irregular, and the flow may vary from cycle to cycle. Occasionally, bleeding can occur without ovulation. This is called dysfunctional, or anovulatory bleeding. The cycle often begins early or late, without premenstrual symptoms. Bleeding can go on for weeks, with variable flow. Often the bleeding is bright red. Although the bleeding will eventually stop, it is best to see your gynecologist who will treat this with progesterone, which will stop the bleeding.
Another phenomenon has been noted. Sometimes a women will ovulate twice in a cycle, the latter being a week before the expected menses. If this occurs, the estrogen level can become quite high, leading to breast tenderness, migraines, heavy bleeding, or even growth of a fibroid tumor. The subsequent cycle may then occur less than 21 days from the previous one.
Occasionally a women will experience a "real" period one to three years after her last normal period. She will describe it as being typical in premenstrual symptoms and amount of flow. She most likely did ovulate, and did have a real period, but any bleeding that falls outside of the first year after the last menses must be evaluated.
Abnormal bleeding patterns would include irregular spotting or flow at irregular intervals. Bleeding after intercourse is not normal. Heavy bleeding requiring changing a tampon or pad every hour would be considered excessive, and would require medical attention and evaluation. Keeping a menstrual calendar is a great way to monitor bleeding patterns, and will help you doctor determine if bleeding is normal or not. Any bleeding which occurs more than one year after the last menstrual period is a red flag, could indicate endometrial cancer, and requires a medical evaluation.
The time from the beginning of changes in menstrual cycle to the last menstrual period is 4-8 years, on average.