Definition of Secondary amenorrhea:

Secondary amenorrhea occurs when a woman who has been having normal menstrual cycles stops getting her periods for 6 or more months.

Amenorrhea is when a woman does not get her monthly menstrual cycle, or period.

See also:

• Menstruation - Absent
• Primary amenorrhea

Causes, incidence, and risk factors:

Women who are pregnant, breastfeeding, or in menopause are not considered to have secondary amenorrhea.

Women who are taking birth control pills or receive hormone shots such as Depo-Provera may not have any monthly bleeding. When they stop taking these hormones, their periods may not return for more than 6 months.

You are more likely to have amenorrhea if you:

• Are obese
• Exercise excessively and for long periods of time
• Have less than 15% - 17% body fat
• Have severe anxiety or emotional distress
• Lose a lot of weight suddenly (for example, with a strict diet or after gastric bypass surgery)

Other causes include:

• Brain (pituitary) tumors
• Polycystic ovarian syndrome
• Premature ovarian failure
• Thyroid dysfunction

The following drugs may also cause missed periods:

• Busulfan
• Chemotherapy drugs for cancer
• Chlorambucil
• Cyclophosphamide
• Phenothiazines

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. Scarring may also be caused by some severe pelvic infections.