When a specific cause of a couple’s infertility cannot be identified it is termed “Infertility of Unknown Causes”. This does not mean that there is no reason for infertility, rather it cannot be diagnosed. Great strides have been made in reproductive medicine over the last ten years but much research remains to be done. The percentage of couples falling within the category will continue to decline as new causes of infertility are discovered.
Certain undiagnosed sperm defects and eggs that will not fertilize fall within this category. There are likely genetically based abnormalities that affect the cellular mechanics of the sperm and/or egg. Sometimes the embryo will not implant into the endometrium and no specific cause can be identified.
Treatment of “infertility of unknown causes may consist of intrauterine insemination followed by IVF if pregnancy does not occur. Intracytoplasmic sperm injection will often be recommended since there could be an “unknown” male factor infertility component. Assisted hatching may also be employed to help the embryo break out of its shell (zona pellucida) and facilitate implantation in the uterine wall (endometrium).