ObjectiveTo systematically review the association of micronucleus and polycystic ovary syndrome (PCOS).MethodsPubMed, OVID, Elsevier, CNKI, WanFang Data and CBM databases were electronically searched to collect case-control studies on the association of micronucleus and PCOS. 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 5 case-control studies were included, in which 170 patients were in the case group and 148 in the control group. The results of meta-analysis showed: there were significant differences between the two groups for micronucleus frequency (MD=2.02%, 95%CI 1.63% to 2.41%, P<0.000 01) in peripheral blood lymphocytes and micro nucleated cells frequency (MD=2.43%, 95%CI 0.10% to 4.76%, P=0.04) in oral epithelial cells.ConclusionThe current evidence shows that micronucleus is associated with PCOS. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify above conclusion.