A periodic change occurring in human females (and the higher apes), consisting chiefly of a flow of blood from the cavity of the womb (UTERUS) and slight constitutional disturbances. It usually begins between the ages of 11 and 15, although its onset may be delayed until as late as 20, or may begin as early as 9 or 10. Along with its first appearance, the body develops secondary sex characteristics: for example, enlargement of the BREASTS, and axillary and pubic hair.
An individual's menstrual periods can last anything from 2–8 days. In most it recurs regularly, at intervals of 28 or 30 days, less often with intervals of 21 or 27 days, until the age of 40 or 50 when it stops altogether – as a rule ceasing early if it has begun early, and vice versa. It usually ceases only during pregnancy and while breast feeding. The final 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 lining (ENDOMETRIUM) is regenerated under the influence of the hormone oestradiol. About a fortnight after the beginning of menstruation, great development of the endometrial glands takes place under the influence of progesterone, the hormone secreted by the CORPUS LUTEUM. These changes are designed to receive a fertilised OVUM (egg). In the absence of fertilisation the uterine endometrium breaks down in the subsequent menstrual discharge.
Many women experience problems such as absent, excessive or painful menstruation.
This is absent menstruation; if it has never occurred, the amenorrhoea is primary; if it ceases after having become established it is secondary. Primary amenorrhoea may be the first clue to a chromosomal abnormality (see CHROMOSOMES) or malformation of the genital tract.
There are many causes of secondary amenorrhoea: commonest is pregnancy, followed by psychological stress, eating disorders and poor nutrition or loss of weight by dieting; also any serious underlying disease such as TUBERCULOSIS or MALARIA may cause amenorrhoea. Excessive secretion of PROLACTIN, either because of a micro-adenoma of the PITUITARY GLAND or drug induced, will cause amenorrhoea and possibly GALACTORRHOEA as well. Other hormonal causes include failure of the pituitary gland to produce gonadotrophic hormones (see GONADOTROPHINS); excessive production of cortisol, as in CUSHING'S SYNDROME, or of androgens (see ANDROGEN), as in ADRENOGENITAL SYNDROME or POLYCYSTIC OVARY SYNDROME; and stopping use of the oral contraceptive pill. It may also be associated with both hypothyroidism (see under THYROID GLAND, DISEASES OF) and OBESITY.
Amenorrhoea can often be successfully treated to allow conception. When weight loss is the cause, restoring body weight can result in spontaneous menstruation (EATING DISORDERS – Anorexia nervosa). Patients with raised concentration of serum gonadotrophin hormones have primary ovarian failure, and this may be uncorrectable, but taking cyclical oestrogen/progestogen medication will usually establish regular withdrawal bleeds without helping with fertility. In mild pituitary failure, menstruation may return after treatment with clomiphene.
This is a change from the normal monthly cycle of menstruation, and may affect the duration of bleeding or the amount of blood lost, possibly from an imbalance 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 show as an ‘irregularity’, as can an early miscarriage (see ABORTION). Disorders of the uterus, ovaries or other organs in the pelvic cavity can also cause irregular menstruation.
Abnormal bleeding from the uterus during regular menstruation. Some women have this problem occasionally, some quite frequently and others never. One cause is an imbalance of progesterone and oestrogen hormones leading to an abnormal increase in the lining (endometrium) of the uterus, which increases the amount of ‘bleeding’ tissue. Other causes include FIBROIDs, POLYPs, PELVIC INFLAMMATORY DISEASE (PID) or an intrauterine contraceptive device (IUD – see under CONTRACEPTION). Sometimes no physical reason can be identified.
Treatment depends on how severe is the loss of blood (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. Medication is the usual option for women without evidence of a serious underlying cause or while awaiting results of tests. The first choice is often an intrauterine device which releases the hormone levonorgestrel (Mirena®). Next best may be NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) or tranexamic acid, which inhibits the breakdown of fibrin (FIBRINOLYSIS). Hormones such as dydrogesterone (by mouth) are, for many doctors and patients, third choice.
Women with persistent intermenstrual bleeding should be referred to a specialist, as should all those aged over 45 and others in whom medical treatment has been ineffective. They may need a BIOPSY from the endometrium to rule out any possibility of cancer or simple endometrial overgrowth; a specialised endoscope – a hysteroscope – can be inserted through the vagina into the uterus to visualise the lining, for example in order to see whether there are fibroids. Hormonal treatments not available to general practitioners can be used for certain women; others may need surgery – for example if they have a serious underlying disease of the uterus, or if all medical treatment has failed and the patient requests surgery, after being fully informed about the risks and benefits. For such women, and they have no wish for a further pregnancy, operations include endometrial ablation, in which the lining of the womb is removed by endoscopic thermal balloons, microwaves, radio waves or CRYOSURGERY. HYSTERECTOMY (removing the uterus) has become a much less commonly performed operation than in the past: removing the ovaries at the same time is recommended only if there is a family history of breast or ovarian cancer, symptoms caused by ovarian dysfunction, such as severe premenstrual tension not responding to medication, or if a fully informed patient requests the operation.
This varies from discomfort to serious pain, and sometimes includes vomiting and general malaise. 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 offer advice and support, which in itself may resolve the dysmenorrhoea. Analgesics or non-steroidal anti-inflammatories (NSAIDs) may help, as may a combined oral contraceptive pill.
Inflammation of the uterus, ovaries or FALLOPIAN TUBES is a common cause of dysmenorrhoea occurring for the first time late in life, especially when the condition follows the birth of a child. In this case the pain exists more or less at all times, but is aggravated with periods. Treatment with analgesics and remedying the underlying cause is called for. Referral to a specialist is recommended if symptoms are severe, examination reveals any abnormality, there are other gynaecological symptoms or if medication has not helped.