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

See also:

Menstruation - Absent

Primary amenorrhea

About 4% of women have secondary amenorrhea. There are many reasons for missing a period.

You are at an increased risk of secondary amenorrhea if you engage in extreme and prolonged exercise (particularly without adequate conditioning), have less than 15 - 17% body fat, are obese, or take hormonal supplements.

Anxiety and emotional distress can also cause a missed period.

The following drugs may also cause missed periods: 

• Busulfan
• Chlorambucil
• Cyclophosphamide
• Phenothiazines 
• Oral contraceptives
• Non-oral contraceptives such as Depo-Provera

Also, procedures such as a dilation and curettage (D and C) can cause a woman to develop amenorrhea if scar tissue develops within the uterine cavity.

• 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, dry vagina, increased hair growth in a "male" pattern (hirsutism), voice changes, and breast size changes. If amenorrhea is caused by a pituitary tumor, other symptoms related to the tumor such as visual loss, may be present.

The doctor will probably do a pelvic examination. Physical and pelvic examinations must rule out pregnancy before other diagnostic testing begins. The patient may be referred for psychological counseling if anxiety is causing the condition.

Diagnostic tests that may be performed include:

• Endometrial biopsy
• Progestin withdrawal
• Prolactin level
• Serum hormone levels such as testosterone levels
• Pregnancy test (serum HCG)
• Follicle stimulating hormone (FSH level)
• Luteinizing hormone (LH level)
• Thyroid stimulating hormone (TSH)
• Karyotype to rule out the presence of Y chromosome abnormality
• CT scan of the head may be done if a pituitary tumor is suspected