The diagnosis of unexplained Infertility is made after a standard fertility work up fails to provide an explanation for a couple's infertility.
About 15% of couples that have been trying to conceive for a year without success will have normal findings after a standard fertility work up. By definition, these couples have unexplained infertility. Why is their infertility unexplained? The simple answer is there are limitations to our ability to evaluate human fertility. Even the best, most thorough testing has limitations.