Statistics show that female factors account for approximately 40% of all infertility cases and male factors account for a further 40%. In the remaining 20% of cases, fertility is unexplained.
Sometimes a minor problem with both partners can impair fertility, even though the couple may have had no problems in other relationships. At times, there may be no scientific explanation for infertility.
In the majority of cases, the failure to reach a diagnosis is not due to inadequate investigations, but is perhaps due to other factors which are impossible to assess using conventional methods.
For example, assessing whether the eggs have actually been released at the time of supposed ovulation, whether the eggs are deposited into the fallopian tubes, whether the sperm are capable of reaching the site of fertilisation within 24-48 hours of their production or whether the eggs can be fertilised by the sperm.
In cases with unexplained infertility, assisted conception in the form of IVF is both diagnostic and therapeutic. For example, if the eggs are not released by performing egg collection or if the tubes are not picking up the eggs, they can be by-passed when IVF is performed. Finally, fertilisation itself can be diagnosed by the performance of IVF.