Infertility

Causes

Infertility and its causes

Infertility, has already been defined as the failure of a couple to conceive after having had normal unprotected intercourse for a period of one year. The importance of this definition is that it acts solely as a guide to both doctor and couple as to when investigation for infertility should commence.

At best, the objective of infertility treatment is to restore normal fertility. A pregnancy cannot be guaranteed! As previously explained, time is a factor of normal fertility and thus the reason for making timely investigation is to use this time efficiently rather than wastefully. There are a number of general and specific considerations to be made when approaching the problem of infertility.

General Considerations

Infertility is a common condition affecting approximately one in six couples (15%). To date at least thirteen of the fifteen percent (85%) will conceive! Infertility is a problem affecting a couple and not an isolated individual. Fertility represents more than the sum of a couple's individual fertility. Thus Male A, who has a slight problem, together with Female B, who has a slight problem, may together be infertile. However, Male A with Female C, who is highly fertile, may have no problem at all. This represents the concept of multiple minor factor infertility. Because ultimately infertility is due to a disease process, neither partner should ever consider it as "my fault". No one should be blamed! In almost half the number of infertile couples the cause is due to the male partner.

In approximately fifteen percent of couples there will be more than one causative factor of infertility. Unfortunately, it may not be possible to find the cause of infertility in approximately one to two percent of couples. Their infertility is unexplained. Even so, treatment is available.

Specific Considerations

For a chance of a pregnancy to occur, the three basic requirements of a normal egg, normal sperm and normal pathway must be fulfilled. The process does not end there, however, and other types of infertility will be discussed later. It should be appreciated that in an article of this nature, it would be both impossible and impractical to give a complete list of infertility causes. However, your own doctor should be able to advise into which of the following category(s) your problem or problems fall.

1. Problems related to eggs
   • Absence of ova in ovaries or absence of ovaries themselves. (Rare)
   • Failure of maturation or release of eggs (anovulation) (Common)
   • Failure of the egg to reach the Fallopian tubes (Common)
   • Apparent lack of quality of egg
2. Problems related to sperm
   • Absence of sperm in testicles, or absence of testicles themselves (Rare)
   • Failure of normal maturation and release of sperm (Common)
   • Ejaculation of sperm into the bladder (retrograde ejaculation) (Rare)
3. Problems related to the pathway
   • Problems of the vagina (Rare)
   • Problems of the cervix (uncommon)
   • Problems of the uterus (Fairly common)
   • Problems of the Fallopian tubes (Common)
4. Endometriosis
5. Multiple Minor Factor Infertility

The problem of multiple minor factor infertility is probably more common than we realise. The degree of infertility that this condition causes is unfortunately out of proportion to the degree of the medical problems found. This results in certain medical practitioners missing the diagnosis and minimising the significance of certain test results.

For example:

The male will have a semen analysis with a report that his count is slightly below normal. In addition the female ovulates irregularly. This couple were reassured that there is nothing really wrong with them. The effect of these minor factors on a couple's fertility can be seen in the following table and their frustration understood.

Additional causes of Infertility

Up until now we have assumed that if an egg and sperm meet in the tube, fertilisation of the egg must take place, leading to the formation of an embryo and ultimately an ongoing pregnancy.

However, this is not necessarily correct. Although at present it is difficult to prove, there is definitely reason(s) to believe that the cause(s) of infertility in certain couples may be due to:-

The inability of the sperm to penetrate and fertilise the egg.
Failure of the egg to divide and grow after fertilisation.
Failure of the embryo to hatch
Failure of the embryo to implant into the wall of the uterus.
Recurrent loss or losses of early pregnancies/ recurrent abortions

One of the problems of investigating the above, is that many of these functions are hidden, normally occurring in the Fallopian tube or Uterus. With the developments in IVF and ICSI some of these previously "hidden" processes have been exposed in the laboratory and this combined with developments in genetics and testing eg PGD are assisting us in treating couples.