A periodic change occurring in (female) human beings and the higher apes, consisting chie?y in a ?ow of blood from the cavity of the womb (UTERUS) and associated with various slight constitutional disturbances. It begins between the ages of 12 and 15, as a rule – although its onset may be delayed until as late as 20, or it may begin as early as ten or 11. Along with its ?rst appearance, the body develops the secondary sex characteristics: for example, enlargement of the BREASTS, and characteristic hair distribution. The duration of each menstrual period varies in di?erent persons from 2– 8 days. It recurs in the great majority of cases with regularity, most commonly at intervals of 28 or 30 days, less often with intervals of 21 or 27 days, and ceasing only during pregnancy and lactation, until the age of 45 or 50 arrives, when it stops altogether – as a rule ceasing early if it has begun early, and vice versa. The ?nal stoppage is known as the MENOPAUSE or the CLIMACTERIC.
Menstruation depends upon a functioning ovary (see OVARIES) and this upon a healthy PITUITARY GLAND. The regular rhythm may depend upon a centre in the HYPOTHALAMUS, which is in close connection with the pituitary. After menstruation, the denuded uterine ENDOMETRIUM is regenerated under the in?uence of the follicular hormone, oestradiol. The epithelium of the endometrium proliferates, and about a fortnight after the beginning of menstruation great development of the endometrial glands takes place under the in?uence of progesterone, the hormone secreted by the CORPUS LUTEUM. These changes are made for the reception of the fertilised OVUM. In the absence of fertilisation the uterine endometrium breaks down in the subsequent menstrual discharge.
Disorders of menstruation In most healthy women, menstruation proceeds regularly for 30 years or more, with the exceptions connected with childbirth. In many women, however, menstruation may be absent, excessive or painful. The term amenorrhoea is applied to the condition of absent menstruation; the terms menorrhagia and metrorrhagia describe excessive menstrual loss – the former if the excess occurs at the regular periods, and the latter if it is irregular. Dysmenorrhoea is the name given to painful menstruation. AMENORRHOEA If menstruation has never occurred, the amenorrhoea is termed primary; if it ceases after having once become established it is known as secondary amenorrhoea. The only value of these terms is that some patients with either chromosomal abnormalities (see CHROMOSOMES) or malformations of the genital tract fall into the primary category. Otherwise, the age of onset of symptoms is more important.
The causes of amenorrhoea are numerous and treatment requires dealing with the primary cause. The commonest cause is pregnancy; psychological stress or eating disorders can cause amenorrhoea, as can poor nutrition or loss of weight by dieting, and any serious underlying disease such as TUBERCULOSIS or MALARIA. The excess secretion of PROLACTIN, whether this is the result of a micro-adenoma of the pituitary gland or whether it is drug induced, will cause amenorrhoea and possibly GALACTORRHOEA as well. Malfunction of the pituitary gland will result in a failure to produce the gonadotrophic hormones (see GONADOTROPHINS) with consequent amenorrhoea. Excessive production of cortisol, as in CUSHING’S SYNDROME, or of androgens (see ANDROGEN) – as in the adreno-genital syndrome or the polycystic ovary syndrome – will result in amenorrhoea. Amenorrhoea occasionally follows use of the oral contraceptive pill and may be associated with both hypothyroidism (see under THYROID GLAND, DISEASES OF) and OBESITY.
Patients should be reassured that amenorrhoea can often be successfully treated and does not necessarily affect their ability to have normal sexual relations and to conceive. When weight loss is the cause of amenorrhoea, restoration of body weight alone can result in spontaneous menstruation (see also EATING DISORDERS – Anorexia nervosa). Patients with raised concentration of serum gonadotrophin hormones have primary ovarian failure, and this is not amenable to treatment. Cyclical oestrogen/progestogen therapy will usually establish withdrawal bleeding. If the amenorrhoea is due to mild pituitary failure, menstruation may return after treatment with clomiphene, a nonsteroidal agent which competes for oestrogen receptors in the hypothalamus. The patients who are most likely to respond to clomiphene are those who have some evidence of endogenous oestrogen and gonadotrophin production. IRREGULAR MENSTRUATION This is a change from the normal monthly cycle of menstruation, the duration of bleeding or the amount of blood lost (see menorrhagia, below). Such changes may be the result of an upset in the balance of oestrogen and progesterone hormones which between them control the cycle. Cycles may be irregular after the MENARCHE and before the menopause. Unsuspected pregnancy may manifest itself as an ‘irregularity’, as can an early miscarriage (see ABORTION). Disorders of the uterus, ovaries or organs in the pelvic cavity can also cause irregular menstruation. Women with the condition should seek medical advice. MENORRHAGIA Abnormal bleeding from the uterus during menstruation. A woman loses on average about 60 ml of blood during her period; in menorrhagia this can rise to 100 ml. Some women have this problem occasionally, some quite frequently and others never. One cause is an imbalance of progesterone and oestrogen hormones which between them control menstruation: the result is an abnormal increase in the lining (endometrium) of the uterus, which increases the amount of ‘bleeding’ tissue. Other causes include ?broids, polyps, pelvic infection or an intrauterine contraceptive device (IUD – see under CONTRACEPTION). Sometimes no physical reason for menorrhagia can be identi?ed.
Treatment of the disorder will depend on how severe the loss of blood is (some women will become anaemic – see ANAEMIA – and require iron-replacement therapy); the woman’s age; the cause of heavy bleeding; and whether or not she wants children. An increase in menstrual bleeding may occur in the months before the menopause, in which case time may produce a cure. Medical or surgical treatments are available. Non-steroidal anti-in?ammatory drugs may help, as may tranexamic acid, which prevents the breakdown of blood clots in the circulation (FIBRINOLYSIS): this drug can be helpful if an IUD is causing bleeding. Hormones such as dydrogesterone (by mouth) may cure the condition, as may an IUD that releases small quantities of a PROGESTOGEN into the lining of the womb.
Traditionally, surgical intervention was either dilatation and curettage of the womb lining (D & C) or removal of the whole uterus (HYSTERECTOMY). Most surgery is now done using minimally invasive techniques. These do not require the abdomen to be cut open, as an ENDOSCOPE is passed via the vagina into the uterus. Using DIATHERMY or a laser, the surgeon then removes the whole lining of the womb. DYSMENORRHOEA This varies from discomfort to serious pain, and sometimes includes vomiting and general malaise. Anaemia is sometimes a cause of painful menstruation as well as of stoppage of this function.
In?ammation of the uterus, ovaries or FALLOPIAN TUBES is a common cause of dysmenorrhoea which comes on for the ?rst time late in life, especially when the trouble follows the birth of a child. In this case the pain exists more or less at all times, but is aggravated at the periods. Treatment with analgesics and remedying the underlying cause is called for.
Many cases of dysmenorrhoea appear with the beginning of menstrual life, and accompany every period. It has been estimated that 5–10 per cent of girls in their late teens or early 20s are severely incapacitated by dysmenorrhoea for several hours each month. Various causes have been suggested for the pain, one being an excessive production of PROSTAGLANDINS. There may be a psychological factor in some sufferers and, whether this is the result of inadequate sex instruction, fear, family, school or work problems, it is important to o?er advice and support, which in itself may resolve the dysmenorrhoea. Symptomatic relief is of value.
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