Study on the relationship between Matrix metalloproteinases - 9 (MMP-9) gene polymorphism and Recurrent spontaneous abortions Abstract Objective:By determining the normal pregnant women and recurrent spontaneous abortions history woman's matrix metalloproteinases - 9 (MMP-9) gene polymorphism of peripheral blond to probe the relativity between MMP-9 gene polymorphism and recurrent spontaneous abortions. Methods:Using polymerase chain reaction - restriction fragment lengthpolymorphism (PCR - RFLP) analysis method to analyse sixty cases patients who have recurrent abortions history (case group) and 60 cases of normal health early pregnantwomen's (control group) MMP-9 gene polymorphism , Using t test to checkout the difference of age, gestational weeks between the case group and the control group. Comparing two groups gene frequencies and allele frequencise uses the chi-square test(χ2 ) analysis. Calculate odds ratio(OR ) to show relative risk degree,and its 95% confidence interal (CI) . Results:(1) The case group and contr