Most women have between 11 and 13 menstrual periods each year. You may be different: You may have more or fewer. Missed or irregular periods must be looked at in terms of what is normal for you.
Menstrual periods are often irregular during the first few years after menstruation starts. It may take several years for the hormones that control menstruation to reach a balance.
Menstrual periods also may be very irregular at the other end of the menstrual years. Many women realize that they are approaching perimenopause and menopause when their otherwise regular periods become irregular. Menopause occurs when it has been 12 months since you had a menstrual period.
Pregnancy is the most common cause of a missed period. If you might be pregnant, treat yourself as if you are pregnant until you know for sure. Use a home pregnancy test as the first step to finding out whether you are pregnant.