Sub Fertility

About ninety per cent of couples having intercourse with­out using contraception conceive within eighteen months; the other ten per cent are considered to be sub-fertile. This does not necessarily mean they will not be able to have a child together. It does mean that they would benefit from medical investigation, as about fifty per cent of infertile couples who seek help do eventually conceive.

Causes and treatment

Infertility in men may be caused by poor sperm production or obstruction of the route normally taken by sperm to the outside. Impaired sperm production may be due to the testes being at too high a temperature; and hot baths and tight-fitting underwear, particularly for men in sedentary jobs, should be avoided. As the sperm-production cycle takes about three months, however, such advice needs to be followed for a long time before any practical effect is likely. Male infertility may respond to hormone treatment or, if an anatomical abnormality is found obstructing the normal passage of sperm, to surgery. Some couples may be helped by artificial insemination by donor (AID).

Causes of infertility in women which are relatively easy to treat include spasm of the fallopian tubes, cervical narrowing, cervical mucus which is hostile to sperm, and fibroids. In ten to fifteen per cent of cases, infertility in women is caused by failure to ovulate, and in another tWenty per cent by blocked fallopian tubes. Failure to ovulate can some­times be corrected by hormone treatment, though such therapy can have side-effects, and may result in multiple pregnancies.

The commonest cause of blocked fallopian tubes is pre­vious infection leading to the build-up of scar tissue, perhaps as a result of gonorrhoea, abortion, or using an intrauterine contraceptive device. It can sometimes be corrected by surgery, but the success rate is not high and better results have been obtained using the technique of in vitro fertilization. (In vitro is the Latin for 'in glass', another way of saying 'in the laboratory'.) This technique involves collecting the egg from its follicle in the ovary, using a needle and laparoscope under ultrasound guidance. The egg is fertilized in the laboratory using the partner's sperm, and replaced in the uterus, via the cervix. If all goes well, a normal pregnancy and birth will follow.

It has been found that, with this technique, the rate of implantation goes up if more than one embryo at a time is returned to the uterus. It is normally difficult to obtain more than one mature egg at a time, however, so hormonal drugs are used to induce 'superovulation' in which many eggs mature at the same time. Several can be fertilized and those that are not returned to the uterus on that occasion are, in some cases, frozen. This means that if a pregnancy does not become established immediately, more embryos can be thawed and returned to the uterus the following month.

Moral questions surrounding such recent advances in 'reproduction technology', as it is known, are now being raised. Some people are against fertilizing more than one egg at a time in the knowledge that some of them may never have the opportunity to develop; others wish to further medical knowledge by experimenting with the genetic material of the fertilized egg, in the hope of being able to prevent genetic diseases in future.