The causes of infertility can be due to problems that affect the man or the woman, or both. Sometimes no cause is found, despite thorough and up-to-date testing of both partners and this is known as unexplained infertility.
In unexplained infertility abnormalities are likely to be present but not detected by current test available world wide.
By understanding the many steps that go into making a baby it is easy to see that there are many possible problem areas that will not show up on currently available tests.
Possible problems could be that the egg is poor quality, that the egg is not getting into the fallopian tube, sperm may not be able to bind to the egg or get inside correctly (in which case fertilization will not occur), transport of the fertilized egg from the tube to the womb lining may not occur normally or at the right speed, or implantation of a healthy embryo might fail for a variety of reasons.
The quality of the egg quality is critically important and this is the main problem for women as they get older, especially from 40 years and over. These women have eggs a reduced ability to undergo normal and successful fertilization.
Other theories accounting for unexplained infertility are genetic defects in both the man and woman, pelvic abnormalities such as endometriosis that are invisible to the naked eye during surgery, variations in folate pathway genes, dysfunctional immune systems and abnormalities of fallopian tube function.
Treatments for unexplained fertility are recommended based on the length of time a couple have been trying along with the woman’s age. For young couples that have not been trying for over four years, drugs for ovulation are often tried first followed by IUI treatment. Older couples or those who have been trying for over four years will often move to IVF as their first treatment option.