Missed periods

There are many reasons why you may stop having regular periods, including:

• Pregnancy. Many women first discover they are pregnant when they do not begin their menstrual period as usual. Problems with pregnancy, such as an ectopic pregnancy, also can cause a missed period. This is especially true if you have had a tubal ligation.
• Hormonal birth control methods, such as birth control pills or hormonal injections. Also, you may find that it takes your body several months to readjust to regular periods after you stop using birth control pills.
• Other medications, such as chemotherapy or steroids.
• Breast-feeding.
• Low body weight or rapid weight loss.
• Severe stress or lifestyle change.
• Obesity. Missed or irregular periods are common in women who have a body mass index (BMI) of 27 or more.
• Excessive exercise or participation in endurance sports.
• Menopause. Missed or irregular periods may be the first sign that you are entering menopause. During the 2 to 5 years before menopause (perimenopause), you may notice that your periods are irregular.

Other, more serious causes of missed periods include tumors, pituitary disorders, and other glandular problems involving the ovaries, thyroid, or adrenal glands. These problems are rare.

If you are certain that you are not pregnant and you have no other symptoms, you can wait up to 3 months before consulting a health professional. Remember, you can still become pregnant even though you are not menstruating. Practice birth control if you do not wish to become pregnant.