Unexplained recurrent spontaneous abortion(URSA)is one of the most common pregnancy complications in obstetrics and gynecology,which causes serious negative effects on the patient's body,mind and family,and is a major threat to the reproductive health of women of childbearing age.The etiology and pathogenesis of URSA are still unclear,and there is no effective prevention and treatment measures,which is a major difficulty in the field of reproductive health.Studies have shown that single nucleotide polymorphism(SNP)in nitric oxide synthase 3(NOS3)and interleukin 1β(IL-1β)genes are associated with URSA,but the literature results are not consistent.This article reviews the research progress on the correlation between NOS3,IL-1 β gene polymorphisms and URSA.