For lots of people, having babies is very easy - in fact many people spend years trying to avoid pregnancy, using different methods of contraception to make sure that sperm and eggs don't meet by accident. But what happens if pregnancy and babies don't happen when we want them to?
Infertility has always been an issue - Henry VIII got rid of several wives who could not produce him the son and heir he so desperately wanted! The lives of many ordinary people have also been blighted by the inability to have a much wanted child. Although there are many different causes of infertility, for centuries the solutions were few and far between - adopting a child or becoming resigned to childlessness were the main options.
It is almost inevitable that, if a couple cannot have a child, they wonder whose 'fault' it is. For centuries, it was assumed that childlessness was the woman's fault - in the words of the Christian Bible, she was barren. We now know better! Failing to get pregnant can be the result of problems in either partner, or even both.
In about a third of all cases of infertility there is indeed a problem in the way that the body of the woman is working. However in about another third, or even more, it is the reproductive system of the man which is not functioning as it should. The final third of infertility cases are either the result of both the man and the woman in a couple being a bit less fertile than normal, or - the most puzzling of all - both couples are theoretically healthy but pregnancy just doesn't happen.
Female infertility
To find out why a woman is not conceiving doctors look for both physical and chemical causes. One of the first checks will be to see if ovulation is occurring - because no egg = no baby! Sometimes the situation is very stark - there are no eggs in the ovaries so the woman will never conceive naturally. Fortunately this is very rare.
In many women who do not ovulate the cause is easier to deal with. Some women don't make enough FSH to stimulate the release of the ripe eggs from the ovary and others don't make any at all. Synthetic hormones can be used which will replace natural FSH, bringing about ovulation and so, hopefully pregnancy.
The most common female physical problem preventing pregnancy is when the Fallopian tubes are twisted, scarred or blocked in some way. This prevents the sperm from meeting the egg and even more importantly stops the egg, fertilised or not, from travelling along to the uterus. 30% of female infertility is the result of damaged Fallopian tubes.
Sometimes a technique which involves tiny instruments placed into the Fallopian tubes can be used to try and reopen them, but the technique itself can damage the very delicate tubes. When the tubes are badly damaged or blocked then the only hope of a solution is IVF.
Male infertility
There are two crucial factors in male infertility - is the man is producing sperm in his semen, and are they normal, healthy and active? The answer to both of these questions comes from a careful examination of a man's semen.
In normal healthy semen there will be hundreds of millions of sperm. In fact the lowest number of sperm counted as normal is 20 million sperm per cm3 of semen! Once the sperm count falls below this level it begins to affect fertility. If the sperm count is just a bit below normal there are things which a man can do to increase the numbers - all of them very low tech! If the testes get too warm, the level of sperm production falls, so cool showers or baths, baggy underwear and loose clothing can help to increase the sperm count. Cutting out smoking and drinking alcohol - both known to lower the sperm count - can also help increase sperm numbers.
The overall sperm count is important, but the ability of sperm to fertilise eggs successfully depends on more than numbers. For the man to be fertile his sperm need to have actively lashing tails and around 50% of them must swim forward in straight lines rather than round and round in circles.
It is also very important that the semen doesn't contain too many abnormal sperm. Every man produces a certain number of sperm with two heads instead of one, or with two tails, or broken necks. But if the percentage of these abnormal sperm gets too high, then the chances of a successful pregnancy fall.
Overcoming male infertility has not been easy. Until recently the best hope was for the woman to be treated with healthy sperm given by an unknown donor, often mixed with some of her partner's sperm. However, some of the latest developments of IVF involve using a single normal sperm and injecting it into an egg cell which is then replaced inside the mother to develop. This exciting new development may lead to treatment for almost all men with fertility problems, as the numbers of men who produce no healthy sperm at all is relatively small.
What can we do about it?
In the last fifty years it has become increasingly possible to treat and overcome at least some forms of infertility. A wide variety of options are now available for couples who cannot produce a child naturally. These range from simple tests based on the levels of reproductive hormones in the blood or the urine which make it possible to pinpoint when a woman is most likely to get pregnant, through to techniques such as in vitro fertilisation or IVF.
Like most scientific breakthroughs, our increased ability to control human fertility is something of a mixed blessing. It can bring great personal happiness to couples who would otherwise be unable to have a child. At the same time it also opens up many questions about the embryos which are created and then not needed, and the possibilities for changing the inherited material of the embryos before they are returned to the mother. As new and ever more sophisticated treatments for infertility are discovered, the ethics of each need to be discussed. Yet the driving force behind the whole technology remains the desperate desire of infertile couples to have a child of their own.
