Causes of Infertility in Women

Fertility is an emerging problem in both developing and developed countries. It is postulated that as many as 1 in 6 couples suffer from some degree of infertility. This is a considerably high ratio compared with the distant past.

Human reproduction is a complex process mixed with the right combination of factors and a stroke of luck. In order for pregnancy to happen, all the processes which include presence of sperms when the mature egg is released from the ovary during ovulation, the fertilization of the egg by the sperm and successful implantation of the resulting fertilized egg (embryo) on the inner lining of the womb must happen at the right time.

Any alteration or disruption can lead to a decline in the ability to conceive. There are a number of factors that can disrupt a woman’s reproductive process. Infertility can be caused by one or a combination of these factors. Following are explanations on some contributing factors.

Ovarian Causes

Problems with ovulation are the most common causes accounting for 25% to 30% of female infertility.

During a normal ovulation cycle during a woman’s reproductive years, a woman’s ovary will release a normal and ripe egg or ovium. Anovulation is a condition in which the ovary does not release a ripened egg each month. Naturally, with no egg available for sperm, a woman cannot become pregnant.

In almost half of the cases of anovulation, the ovaries do not produce normal mature eggs.  Ovulation usually does not happen if the eggs are immature thus rendering the chances of fertilization remote. This can occur when there is a condition that leads to an imbalance of the hormones responsible for ovulation. One of the commonest is Polycystic Ovarian Syndrome (PCOS).

PCOS is a condition that is classically characterized by irregular scanty (very light) periods, persistent weight gain and infertility. In more severe cases, women with PCOS may have excessive body hair growth. Besides causing infertility, untreated PCOS may lead to higher risk of womb cancer, heart disease and hypertension.

Other less common hormonal causes of ovulatory disturbances could be caused by physical injury or by the presence of a tumour in or near the brain. These rarer hormonal disturbances include malfunction of the hypothalamus (the part of the brain that regulates the hormone responsible for stimulation of the ovaries to produce eggs as well as ensuring that the mature eggs are released) and malfunction of the pituitary gland (the organ that produces these hormones).

Another hormonal cause called hyperprolactinaemia is a condition characterized by elevated levels of prolactin (the hormone that is responsible for the production of breast milk which can inhibit ovulation). Note that prolactin levels are normally high during pregnancy and lactation, and also in severe stress. The effects of raised prolactin are:

  • In women, hyperprolactinaemia leads to menstrual dysfunction.
  • In men, hyperprolactinaemia has a direct, reversible effect on the hypothalamus, causing reduced libido and erectile dysfunction

The normal function of the ovary could be disrupted by premature ovarian failure, which is a rare and unexplainable condition. Premature ovarian failure occurs when the ovaries stop working before age 40. You may have no eggs or only a few eggs. Depending on the cause, premature ovarian failure may develop as early as the teen years, or the problem may have been present from birth.

A woman who has premature ovarian failure is very likely to have irregular or no periods, infertility problems, and menopause-like symptoms. Some studies have suggested a genetic link.

An even rarer condition is the congenital absence of the ovaries. This means that the woman is naturally born without any ovaries as part of her reproductive system

Dysfunction or obstruction of the fallopian tubes

The fallopian tube is the place in which fertilization occurs during natural conception.  A poorly functioning tube or an obstructed tube will hamper the possibility of the sperm being able to reach the egg, thus reducing the chances of fertilization.

Infections, which are usually transmitted sexually, can lead to inflammation of the tubes resulting in the scarring and damage of the fallopian tubes. In severe cases, the tubes may be swollen as a result of fluid collecting in the obstructed ends of the tubes.

Previous surgeries on the tubes during cases such as ectopic pregnancies could also damage and cause inflammation and scarring to the tubes.  Adhesions of the tube to the surrounding organs following previous pelvic or abdominal surgery may further reduce it’s mobility.

Abnormal Womb

These include presence of fibroids which involves the inner lining of the womb as well as polyps.  Congenital abnormalities which lead to abnormality of the shape of the womb are rare.

Endometriosis

Endometriosis is a common cause of infertility throughout the world. It is characterized by the presence of the cells in the inner lining of the womb in other parts of the body, mainly in the ovaries, tubes and the pelvic cavity. This leads to inflammation which may cause infertility as a result of excessive damage and scarring to the ovaries as well as tubal obstruction.

Other contributing factors

Apart from biological factors, infertility is also influenced by lifestyle factors such as diet, exercise, smoking, alcohol intake and substance abuse which have a direct as well as indirect influence on ovulation.

Dr Aldrin Lie Tze Min

Consultant Obstetrician & Gynaecologist, Fertility Specialist
Resident Consultant
Specialty
Obstetrics & Gynaecology, Fertility Specialist
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BSc. (UKM) , MD (UKM) , M. MED O & G (Malaya)
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