Amenorrhea is the absence of menstruation. 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.

See also:

• Menstruation - absent
• Secondary amenorrhea

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:

• Adrenogenital syndrome
• Chromosomal abnormalities such as Turner syndrome or Sawyer syndrome
• Congenital heart disease (cyanotic)
• Congenital adrenal hyperplasia
• Craniopharyngioma
• Chronic (long-term) illnesses
• Cushing's disease
• Cystic fibrosis
• Extreme weight loss
• Genital abnormalities present since birth (absence of the uterus or vagina, vaginal septum, cervical stenosis, imperforate hymen)
• Gonadal dysgenesis
• Hypoglycemia
• Hypothyroidism and hyperthyroidism
• Hypogonadotropic hypogonadism
• Hyperprolactinemia
• Malnutrition
• Obesity
• Prader-Willi syndrome
• Pregnancy
• Polycystic ovarian disease
• Testicular feminization
• True hermaphroditism
• Tumors of the pituitary or adrenal glands
• Tumors of the ovaries