Causes of Infertility

The complex nature of the processes and interactions involved in egg/sperm production and fertilisation means that something can go wrong at various stages of the process.

Infertility is usually defined as the inability of a couple to conceive after one year of unprotected intercourse. However, younger couples may be encouraged to wait for up to two years by some doctors before seeking treatment, while women over 35 or those with certain medical conditions, such as diabetes, should only wait six months.

About one in six couples concerned end up seeking help. Within this group, the cause of infertility is found to lie with the woman in up to 40 per cent of cases and with the man about 30 per cent of the time. In the remaining cases, either both partners are found to have reduced fertility or the cause cannot be determined.

Female factors

  • Hormonal / ovulation: Hormonal problems affect follicular development as well as ovulation. Problems with ovulation are the most common cause for female infertility and account for up to a third of all cases.
  • Tubal problems: Damage to the fallopian tubes is another common reason for infertility, preventing the egg from travelling down, affecting fertilisation or passage to the uterus.
  • Uterine problems: Fibroids and polyps in the uterus can also cause problems with fertility. Abnormalities of the uterine cavity mostly cause recurrent pregnancy losses.
  • Endometriosis can be a key problem in the pelvis. In this condition, developing cells from the endometrium break away and stick to the ovaries and fallopian tubes affecting the way they function.
  • Cervix / vaginal problems: Structural abnormalities of the vagina or cervix can affect fertility as can the physical characteristics of the cervical mucus. The mucus can be hostile to sperm, perhaps containing antibodies or thick enough to block the movement of the sperm.
  • Hyperprolactinaemia: This is a condition where excess levels of the hormone prolactin are found in the blood. This can cause symptoms including irregular or absent menstrual cycles, infertility and increased production of breast milk.

Male factors
This seems to be on the increase over the last few decades. For centuries infertility was seen to be a predominantly female problem - only in recent times, men’s reproductive capabilities have come under scrutiny. Over the last 10 to 15 years much research has been done. We are still not able to understand everything about male infertility, but a lot of newer methods of treatment are available. Daily lifestyle has got a lot to do with poor semen quality - artificial chemicals in pesticides (used in growing vegetables), hormones (meat producing), chemicals in water, polluted air, alcohol and smoking has been implicated. Our exposure to radiation, certain drugs, daily stress, sexually transmitted diseases, etc. are some of the other important factors. If anatomical abnormalities are present the male partner will be referred to an Urologist.

  • Sperm potency: The vast majority of cases of male infertility are due to a low sperm count, which is generally associated with a high rate of sperm defects (size, shape and movement).
  • Hormonal imbalances: Hormonal imbalances related to FSH and LH do occur in men but are not very common.
  • Testicular failure: Some men are found to have no sperm in their semen. This could be due to a failure to ejaculate or a failure of the testes to produce sperm.
  • Varicocele: These are varicose veins in one or both scrotums, and are the most common anatomical abnormality in infertile men.
  • Tubal blockage: Damage as a result of infections can prevent the sperm from getting into the semen. Occasionally the ejaculate of some men is diverted into the bladder.
  • Sperm antibodies: A small group of men actually produce antibodies against their own sperm. This cause accounts for around 10 percent of unexplained male infertility.

Joint infertility problems

Of the number of cases of infertility where the problem lies with both partners, some of the causes may be straightforward and quite simple to remedy. As the window of opportunity to fertilise an egg is quite limited in a woman's monthly cycle, the frequency and timing of intercourse may be factors. Some cases have been found to be related to technique (the sperm is not deposited high enough in the vagina). Fertility is also reduced with increasing age, especially in women. In men, testosterone levels can decline with age but not in the dramatic manner seen in women. Men continue to produce sperm but their motility and quality are reduced with advancing age.