Recurrent miscarriage (RM) affects between 1-2% of fertile couples and is a clinical condition of heterogeneous etiology. Parental structural chromosome rearrangements are reported in 3-8% of couples suffering recurrent miscarriage and testing of both partners is therefore recommended. Conventional cytogenetic analysis of miscarriage tissue from women with a history of RM has detected a 26-57% abnormality rate. In the RM population, the prevalence of reported uterine malformations range widely from between 1.8% to 37.6%. Diagnostic tools for detecting uterine anomalies include two- and three-dimensional ultrasound, hysteroscopy, laparoscopy and magnetic resonance imaging (MRI). The antiphospholipid syndrome (APS) remains entrenched as one of the most studied factors associated with RM. Natural killer (NK) cells are found in peripheral blood and within the endometrium and have been associated with RM. Presently, many of the RM investigations are controversial because of limited studies, inconsistent terminology and small and poorly designed treatment studies.