The problem may lie in one of these areas:
• The woman—70 to 75 per cent of infertile couples have a female factor.
• The man—30 to 35 per cent have a male factor.
• The couple—40 per cent of infertile couples have more than one factor. In some couples no cause will be identified.
However, the most common causes of infertility are:
• Anovulation (not producing an egg)—about 30 to 40 per cent of infertile couples have this problem.
• Having blocked fallopian tubes—about 20 per cent.
• Sperm problems—about 20 to 30 per cent.
Rarer causes include problems with the uterus, cervix, chromosomes and male anatomy.
Sperm problems. Hormones controlling the production of sperm (similar to those controlling egg production in women) are circulated from the hypothalamus and pitiutary. They act on the sperm-making cells in the testes (balls), so if there is not enough of the right mix of hormones around, or the message is not getting through, there may not be many good quality sperm made.
The job of the testes is to make sperm. The sperm are stored in the epididymis (attached to each testis) and the seminal vesicles (in the pelvis). When a man ejaculates during an orgasm, sperm, mixed with a liquid called seminal fluid, squirt out of the penis via the urethra (the tube which also carries urine from the bladder to the outside). Doesn’t sound particularly romantic, but in general it is effective. When it doesn’t work, it may be for a variety of reasons.
The cells of the testes may not be capable of responding to the signal sent by the hormones, and may not be producing any, or adequate sperm. This may be because the testes have developed that way (congenital infertility), or have had something happen to them at some time (acquired infertility). Having abnormal sperm or low sperm counts does not affect sexual performance; infertile and subfertile men usually have otherwise perfectly normal sexual function, and still ejaculate seminal fluid, often with no idea that something is wrong until their partner does not become pregnant.
Causes of congenital problems include undescended, or incompletely descended testes. The testes are meant to live in the scrotum (skin sac below the penis), where the temperature and conditions for sperm making are ideal. During the development of the foetus the testes migrate from the abdomen (near the kidneys) to the scrotum. If they don’t make it all the way to the scrotum the temperature around the testes is usually too high to make sperm. Little boy babies who have incompletely descended testes can have an operation to bring them down to the scrotum, to prevent them being infertile later in life.
Acquired fertility problems include damage to the testes. This may happen because of infections (mumps, gonorrhoea, chlamydia, syphilis and others), trauma (such as direct trauma from an accident, severe bruising), or torsion of the testis (which is where the testis twists on its attachment, and cuts off its own blood supply—a very painful condition. Prompt surgical correction is required to fix it). High-dose irradiation directly to the area, or some forms of chemotherapy, which are both treatments used in the treatment of certain cancers, may damage the sperm-making ability, and people are usually informed of this risk before undergoing such treatment.
Tests of semen performed for investigation of infertility look at several dip ferent factors. They measure the amount of semen, how many sperm there are, and the shape and appearance of the sperm. They look at how many of the sperm are moving in a normal way.