Health Guide » 
Topic Overview
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.
Missed or irregular periods have many causes. Pregnancy is usually the first cause to be considered, but other common causes are:
Lifestyle changes. Examples include:
- Excessive weight loss or gain.
- Increased exercise (missed periods are common in endurance athletes).
- Extreme emotional stress.
- Travel.
- Medications, such as hormonal birth control methods, which may cause lighter, less frequent, more frequent, or skipped periods.
- Eating disorders, such as anorexia or bulimia.
- Menopause and the 2 to 5 years just prior to menopause (perimenopause).
The start of menstrual periods (menarche). For the first few years of menstruation, periods may be irregular. - Hormonal abnormalities , which cause fluctuating levels of the hormones needed to support menstruation.
- Medications other than birth control pills, such as steroids, tranquilizers, diet pills, or recreational drugs.
- Problems with the pelvic organs, such as imperforate hymen or polycystic ovary syndrome.
- Breast-feeding.
- Inflammatory bowel disease.
If you've skipped a period, try to relax. Restoring your life to emotional and physical balance can help. Many women miss periods now and then. Unless you are pregnant, chances are your cycle will return to normal next month. If you might be pregnant, treat yourself as if you are until you know for sure. Use a home pregnancy test as the first step to finding out whether you are pregnant.
Review the Check Your Symptoms section to determine if and when you need to see a health professional.
