Definition of Amenorrhea - primary:

Amenorrhea is the absence of menstruation. It refers to missing periods in a female age 16 or older.

Causes, incidence, and risk factors:

Most girls begin menstruating between ages 9 and 18, with an average around 12 years old. Primary amenorrhea is not considered to have occurred until a girl is beyond age 16, if she has undergone other normal changes that occur during puberty. Primary amenorrhea may occur with or without other signs of puberty.

There are many possible causes of primary amenorrhea:

• Drastic weight reduction (from poverty, fad dieting, anorexia nervosa, bulimia, very strenuous exercise, or other cause)
• Malnutrition
• Extreme obesity
• Chronic (long term) illnesses
• Genital abnormalities present since birth (absence of the uterus or vagina, vaginal septum, cervical stenosis, imperforate hymen)
• Gonadal dysgenesis
• Hypoglycemia
• Hypothyroidism and hyperthyroidism
• Cystic fibrosis
• Cushing's disease
• Polycystic ovarian disease
• Chromosomal abnormalities such as Turner's syndrome (XO) or Sawyer's syndrome (XY)
• Hypogonadotropic hypogonadism
• Hyperprolactinemia
• Testicular feminization
• True hermaphroditism
• Adrenogenital syndrome
• Congenital heart disease (cyanotic)
• Congenital adrenal hyperplasia
• Craniopharyngioma, pituitary tumors, ovarian tumors, adrenal tumors
• Prader-Willi syndrome
• Pregnancy