Absent menstrual periods, either because of absent ovulation (anovulation) or because of absence of, destruction of, or obstruction to the menstrual flow from the uterus, such as with intrauterine adhesions (when it's known as Asherman's syndrome).

Amenorrhea when a woman has never had a spontaneous menstrual period, that is, a period not brought on by hormone treatment.

Absent periods (amenorrhea) when a woman has had at least one previous spontaneous menstrual period, but then menstruation stops.

"Anorexia" means a profound loss of appetite, followed by loss of weight; "nervosa" means that there is a nervous or mental basis for the state, in this case a belief by the person affected, and contrary to the perception of others, that she (very rarely he) is overweight. She stops eating, may induce vomiting, and uses laxatives to keep the intestines empty and the stomach flat. The menstrual periods stop (there is amenorrhea for two reasons: the weight loss and the underlying mental disturbance, both of which cause hypothalamic anovulation. Medical complications from induced vomiting and laxative abuse can be serious, occasionally fatal. Treatment, which includes psychological and psychiatric counseling, is difficult and is not always completely accomplished. It's a condition chiefly of adolescent girls; the younger the patient the better the chance of cure. For fertility, ovulation induction as often required.

The combination of intrauterine adhesions and amenorrhea.

(BMI) An estimate of the amount of fat a person has, calculated by dividing his or her weight (expressed in kilograms) by the square of the height (expressed in meters). Normally between about 20 and 25, although the upper limit is higher with age. A BMI below 20 generally causes oligomenorrhea, then amenorrhea, through anovulation.

Literally, "hidden menstruation". Apparent amenorrhea caused by an obstruction to the outflow of periodic bleeding from the uterus. Causes include an obstruction in the vagina. Typically there is periodic pain coinciding with the timing of the hidden menstrual flow. The causes of cryptomenorrhea include an imperforate hymen.

Diminishment of the endometrium through lack of support by, especially, the hormone estrogen or by the loss, through chronic endometritis and/or injury at curettage under abnormally low estrogen conditions, of subsequent receptiveness to estrogen. Can cause light periods hypomenorrhea or absent periods amenorrhea.

A hormone produced by the hypothalamus of the brain to regulate production and release of the gonadotropins follicle stimulating hormone and luteinising hormone. Can be administered to induce ovulation when it is deficient (particularly in amenorrhea due to weight loss or excessive exercise), but it has to be given in small amounts directly into a vein, every 60 to 90 minutes for the two weeks of a normal follicular phase (with an electronic syringe-driver), mimicking its natural pattern of secretion.

Hair (particularly, 'terminal hair -- hair that is thick and pigmented) on the face, chest (between the breasts or around the nipples), abdomen or thighs that is getting worse, or is worse than other family members, or is worse than usual for one's race. More likely to be important medically if the periods are disturbed (i.e. if there is oligomenorrhea or amenorrhea).

(hPG) A mixture of follicle stimulating hormone (FSH) and luteinising hormone (LH) extracted directly from pituitary glands obtained at autopsies; not used in Australia or elsewhere since 1986, when it was shown that Creutzfeldt-Jakob disease (CJD), a deadly form of dementia, had been transmitted from its use, presumably due to contaminating and infected brain tissue. Before 1986 it had been used mostly for ovulation induction in women with amenorrhea (absent periods) for which other hormones or drugs had not been effective, although sporadic instances of its use for in vitro fertilisation are known in Australia. No new cases of CJD have been reported among former users of hPG since the early 1990s.

An increase in serum prolactin; can be accompanied by galactorrhea and amenorrhea.

Absence of ovulation caused by insufficient GnRH drive from the hypothalamus, so that the pituitary gland doesn't produce enough follicle stimulating hormone. Usually accompanied by absent periods (amenorrhea).

Adhesions inside the endometrial cavity caused by prior infection (endometritis), especially if there has been a curettage during the period of infection, or if curettage is performed in conditions of low estrogen. The circumstances in which this combination is most common are treatment for a missed abortion and treatment of a postpartum hemorrhage (bleeding a few weeks after the birth of a baby). A cause of absent periods amenorrhea, light periods (hypomenorrhea) or recurrent miscarriages.

Congenital absence of gonadotropin releasing hormone in the hypothalamus (causing, in women, primary amenorrhea and anovulation and, in men, failure of puberty) in combination with a congenitally absent sense of smell.

The use of drugs to stimulate the development of follicles in the ovaries to undergo ovulation, such as clomiphene, various preparations containing follicle stimulating hormone (FSH), and human chorionic gonadotropin (hCG). The two main situations for it are: in the treatment of infertility due to anovulation typically when there is oligomenorrhea or amenorrhea; and for superovulation in assisted conception (e.g. in vitro fertilisation and gamete intrafallopian transfer)

A tumor, usually benign, of the pituitary gland, usually resulting in amenorrhea and anovulation. Often there is an increase (sometimes substantial) in serum prolactin. If the tumor is itself secreting prolactin it is called a prolactinoma. But other tumors can occur, some of which secrete other pituitary hormones. The tumor grows inside a confined space with walls of bone called the pituitary fossa: if it is still small and confined to the fossa we call the tumor a microadenoma; if it enlarges the fossa or pushes out of it, it is a macroadenoma, and is both more dangerous and capable of producing visual symptoms and headaches. Diagnosed on a CAT scan or a MRI scan. Prolactin-secreting microadenomas can usually be treated just with drugs.

(PCOS) A syndrome that consists of polycystic ovaries associated with any clinical symptom or sign of too much male hormone effect, such as acne, excess body hair (hirsutism), or long or absent cycles (oligomenorrhea or amenorrhea). Often called polycystic ovarian disease in the US (PCOD).

In medicine the word primary can denote primacy in one of 3 ways: (1) event-wise (e.g. primary amenorrhea is when there has been no precedent -- no prior period -- whereas secondary amenorrhea) follows prior periods, and likewise the distinction between primary infertility and secondary infertility, a distinction based on prior successful pregnancy); (2) developmentally or time-wise (e.g. a primary follicle gives rise to a secondary follicle, then to a tertiary follicle); or (3) causally (e.g. primary ovarian failure is based within the ovary itself, whereas secondary ovarian failure is secondary to failure of gonadotropins). These sort of distinctions is one reason why medical school takes a long time.

Failure of the ovaries to produce enough follicles, because of a problem in the ovary itself, and resulting in depletion of eggs before the age of 40 years (known as premature menopause, a cause of secondary amenorrhea), or maybe even before the age puberty is expected (causing failure of puberty to happen, including primary amenorrhea). Sometimes occurs in spite of good numbers of primordial follicles that (inexplicably, so far) won't develop. The younger the woman, the more likely that an aneuploidy will be found if a karyotype is done on blood or on a biopsy of the ovary. Estrogen replacement therapy is important to prevent general jeopardy to health, including prevention of osteoporosis.

The word is used medically in one of three ways: (1) part of a sequence, as in primary follicle, secondary follicle, tertiary follicle; (2) when a person has a precedent for a contrary state (e.g. secondary amenorrhea, when a woman has had at least one spontaneous menstrual period, but then menstruation stops; secondary dysmenorrhea means periods that have painful after having been not so -- or not-so-much; secondary infertility means having trouble getting pregnant despite having become pregnant successfully in the past); or (3) when the source of dysfunction lies elsewhere (e.g. secondary ovarian failure means ovaries that do not function because, in this example, the pituitary gland on which the ovaries depend is not functioning).

Measurement of testosterone, the chief male sex hormone (androgen) circulating in the blood serum. If increased in women with oligomenorrhea or amenorrhea, indicative of the polycystic ovary syndrome. The free androgen index and free testosterone are more sensitive tests.

A state of intersex in which the karyotype is male (i.e. 46,XY), the gonads are testes (hence also male), but the body is completely unresponsive to testosterone and to its metabolite dihydrotestosterone, so it develops in the female way, with a normal vulva and vagina apparent at birth, and with normal development of the breasts at puberty. Because the testes still secrete anti-Mullerian hormone, there's no uterus. Invariably these children are raised as girls, normal except for their primary amenorrhea and their infertility. Specialist medical supervision is needed, because there is an increased risk of cancer in the abnormal gonads. Synonymous with androgen insensitivity syndrome (complete form).