Idiopathic infertility refers to failure to conceive in a couple who have no definitive cause for infertility. The incidence of idiopathic infertility depends on the selection and age of the study population and to some extent on fertility evaluations . This may account for the variations reported in different studies, though were all in the range of 10 - 20% . Several theories have been tendered on the etiology of unexplained infertility. This includes diminished ovarian reserve , estradiol/progesterone ratio , impaired ovum pick up and deregulation of the immune system . Autoimmune processes and mechanisms are considered as contributing factors in some cases of unexplained infertility in both men and women, particularly when they are directed to antigens expressed in tissues and cells of the reproductive tract and genital secretion. Presence of antibodies to zona pellucida and endometrial antigens in women, are considered possible causes of infertility in a fraction of patients with unexplained infertility.