ObjectivesTo systematically review the association between the level of blocking antibody and recurrent spontaneous abortions.MethodsPubMed, CNKI, CBM, WanFang Data and VIP databases were searched online to collect case-control studies on the association between the level of blocking antibody and recurrent spontaneous abortions from inception to May, 2017. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 12 case-control studies involving 3 413 patients were included. The results of meta-analysis showed that: there was a strong association between the blocking antibody negative and recurrent spontaneous abortions with statistical significance (OR=6.10, 95%CI 2.40 to 15.51, P=0.000 1).ConclusionsCurrent evidence shows that the blocking antibody negative is a risk factor for recurrent spontaneous abortions. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.