Infrequent periods which are abnormal because of hormonal causes
Table of Contents
When does irregular period happen
Sometimes infrequent periods may be abnormal. If periods have previously been regular but they become irregular (coming less often than once every five weeks, or seem to have stopped altogether) then unless the woman s approaching the menopause this may be abnormal. Some women never develop a regular cycle. If after four years or so after a woman starts her periods they are still coming infrequently, then this may be abnormal.
Regular periods are caused by the shedding of the lining of the womb which is dependant on the regular development of the egg. If for some reason a woman produces eggs less frequently than once a month, then her periods will come less often.
The control of the menstrual cycle is very complicated and a very minor hormone imbalance can cause infrequent periods or even switch them off altogether. Hormones produced in the brain and pituitary gland stimulate the growth of the egg in the ovary. The hormones produced by the ovary as the egg develops (estrogen and progesterone) stimulate the growth of the lining of the womb. The balance between these hormones and the precise pattern of their release into the bloodstream are important for the maintenance of normal regular ovulation and menstruation. Minor abnormalities of the pattern of release of these hormones can upset the entire system and cause infrequent periods.
Factors that can influence hormonal imbalance and can lead to irregular periods
Many events can upset the balance of hormones. Conditions which are known to affect the reproductive cycle and result in infrequent periods include the following:
Stress
The reproductive system is very sensitive to stress and some women find that their periods become infrequent if life is particularly stressful. When life settles down the periods usually return to normal.
Weight change
The loss or gain of more than 3-4 kilos may affect the regularity of a woman's periods. It may take some time to get back to normal even after a woman has regained her ideal body weight.
Diet
Women who alter their diet and become vegeterian experience sometimes cessation of periods.
Provided the diet is balanced, this usually resolves.
Exercise
Taking regular strenuous exercise can affect regular menstruation, and many female athletes have irregular periods.
Chronic ill health
Women who already suffer from chronic diseases such as renal disease and hormonal disorders such as diabetes or thyroid disease may have infrequent or absent periods.
Drugs
Some drugs can interfere with regular menstruation, for example antidepressants.
Contraceptives
Some contraceptives, particularly the progestogen-only or mini-pill and the injection (Depo-provera), may cause infrequent or absent periods.
Some women have infrequent periods because of a specific imbalance of reproductive hormones which is not associated with stress, weight loss or any of the other conditions listed above.
Polycystic ovarian syndrome (PCOS)
Some women because of a hormonal imbalance are unable to develop eggs in each month. An ultrasound picture of their ovaries often shows a number of small, immature eggs developing at different rates. It may also be difficult for the ovaries to develop an egg to the point of ovulation. The appearance of small cysts on the ovaries in combination with some clinical signs ( irregular periods, hirsuitism, acne, obesity) is given the term polycystic ovarian syndrome, or PCOS. Almost always the cystic eggs disappear when the next period comes. The irregular growth of eggs in women with PCOS results in irregular and usually infrequent periods. Some women with PCOS may tend to be overweight and troubled with acne and hirsutism (excess hair growth).
Hyperprolactinaemia
An excess of another hormone produced by the hypothalamus called prolactin may also cause infrequent or absent periods. Some women with excess prolactin also start to produce a small amount of milk from their breasts. Some of these women may have a small benign tumour in the pituitary gland which is causing the overproduction of the hormone.
Premature menopause
Although the average age for women reaching the menopause in Britain is 51, some women can develop a premature menopause. It is possible for this to happen as early as 20 years of age, but this is unusual.