If youve been through a number of tests for infertility, yet theres no conclusive answer to why you and your partner havent managed to get pregnant, you may well be given the diagnosis of unexplained infertility.
This means that either nothing really is wrong with you or your partner or that the current available tests are not good enough to pinpoint the problem that is preventing you from falling pregnant.
Around 20% of couples who fail to get pregnant are likely to be given the diagnosis of unexplained fertility.
One reason why this figure is so high is that we are still in the early days of fertility testing and diagnosis.
Professor Robert Harrison, author of The Smart Guide to Infertility (Hammersmith Press) says, So little of male function is capable of being tested beyond routine semen analysis and basic hormonal control.
For instance, what is a normal sperm? How is it that ICSI can still work with non-mature and apparently morphologically abnormal sperm?
Why does conception still occur in so many with negative PCTs? And what is the role of sperm antibodies?
Diagnosis of female malfunction and infertility is also still an imprecise science.
Prof Harrison says, Exact detection of ovulation and abnormalities in the phases of the menstrual cycle are difficult to diagnose with certainty, and results can vary from month to month.
It is also unclear why, even when ovulation and coitus appear to coincide with no other abnormality, conception may still not occur.
In the uterus, the secrets behind implantation and its failure are slowly but surely being unravelled but it cannot yet be routinely tested.
Because the nature of the problem remains undiagnosed in cases of unexplained fertility, many couples will in time find that they fall pregnant long after they had given up hope of having a baby.
It is generally the case that rather than being deemed infertile, a couple in this situation merely suffers from reduced fertility.
Not that this makes the situation any easier to bear for the couple concerned.
General advice for a couple told they are suffering from unexplained fertility, after going through the appropriate tests, is to do nothing specific for six months other than trying to conceive naturally.
This period of time could be greater if you are aged less than 35 or reduced if you are older.
During this time, many couples choose to employ alternative, untested methods of boosting their fertility. Dietary changes, counselling, relaxation methods, acupuncture, have helped in some cases.
Professor Harrison, who founded the Human Assisted Reproduction Ireland (HARI) Unit and is a former chairman of the WHO Taskforce on Infertility, says, 'In one study which followed up couples with unexplained over eight years, I found 46% had at least one pregnancy, 61% of which occurred in a cycle without active therapy of any kind.'
If after the aggreed period, pregnancy has still not occurred, it may then be appropriate to employ medically-based treatments such as ovarian stimulation, artifical insemination, IVF or ICSI.
The Smart Guide to Infertility, by Prof Robert Harrison, is publiched by Hammersmith Press, £14.99.