Secondary amenorrhea is lack of periods for 6 or more months in a woman who has already started menstruation and who is not pregnant, breastfeeding, or in menopause.

See also:

• Menstruation - Absent
• Primary amenorrhea

There are many reasons for missing a period. Polycystic ovarian syndrome is a frequent cause of secondary amenorrhea.

You are also more likely to have secondary amenorrhea if you engage in extreme and prolonged exercise, have less than 15 - 17% body fat, are obese, or take hormonal supplements.

Other causes include:

• Sudden significant weight loss as seen with strict dieting or after gastric bypass surgery
• Anxiety and emotional distress
• Thyroid dysfunction
• Brain (pituitary) tumors
• Premature ovarian failure

The following drugs may also cause missed periods:

• Busulfan
• Chlorambucil
• Cyclophosphamide
• Phenothiazines
• Birth control pills
• Hormone therapy such as Depo-Provera

Also, procedures, such as a dilation and curettage (D and C), can lead to scar tissue formation that may cause a woman to stop menstruating. This is called Asherman syndrome.

• Previously had one or more menstrual periods
• No menstrual period for 6 months or longer

Other symptoms associated with secondary amenorrhea depend on the cause. They may include:

• Headache
• Galactorrhea
• Considerable weight gain or weight loss
• Vaginal dryness
• Increased hair growth in a "male" pattern (hirsutism)
• Voice changes
• Breast size changes

If amenorrhea is caused by a pituitary tumor, other symptoms related to the tumor such as visual loss, may be present.

A physical exam and pelvic exam must be done to rule out pregnancy. A pregnancy test will be done.

Blood tests may be done to check hormone levels. Tests may include:

• Follicle stimulating hormone (FSH level)
• Luteinizing hormone (LH level)
• Prolactin level
• Serum hormone levels such as testosterone levels
• Thyroid stimulating hormone (TSH)

Other tests that may be performed include:

• Endometrial biopsy
• Genetic testing
• MRI of the head
• CT scan of the head

You may be referred to a psychologist if your doctor believes anxiety may be causing the condition.

Treatment depends on the cause of the amenorrhea. Normal menstrual function usually returns after the primary disorder is treated.

For example, if the primary disorder is hypothyroidism, then amenorrhea will be cured when it is treated with thyroid supplements.

If the primary cause is obesity, vigorous athletics, weight loss, or similar factors, treatment recommendations may include a change in one's exercise routine and weight control.

The outcome depends on the cause. Most of the conditions that cause secondary amenorrhea will respond to treatment.

Depending on the cause, amenorrhea may be harmless, or it may be associated with overgrowth of the uterine lining, a condition called endometrial hyperplasia. This can sometimes lead to uterine cancer.

There may be other complications, depending on the cause of the amenorrhea.

Call for an appointment with your primary health care provider or OB/GYN provider if you are a woman and have missed more than one period so that the cause, and appropriate treatment, can be determined.

Prevention depends on the cause. For example, moderate exercise instead of extreme exercise, weight control, and other measures may be helpful.

Lobo RA. Abnormal uterine bleeding: ovulatory and anovulatory dysfunctional uterine bleeding, management of acute and chronic excessive bleeding. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM, eds. Comprehensive Gynecology. 5th ed. Philadelphia, PA: Mosby Elsevier; 2007:chap. 37.

Master-Hunter T, Heiman DL. Amenorrhea: evaluation and treatment. Am Fam Physician. 2006;73(8):1374-1382.