Abstract:Ohjective To investigale the expression level and clinical significance of hsa_eirc_005075 in serum extracelluolar vesicles(EVs) of patients with recurrent spontaneous abortion ( RSA).Methods Fourteen RSA patients and 14 normal pregnant women fromthe Department of Obstetrics and Gynecology ， Qilu Hospital of Shandong University were enrolled in a training set ，and 64 RSA pa-tients and 48 mormal pregnant women were enrolled in a validation set. The expression levels of hsa_circ_0005075 in serum EVs weredetected by the quantitative real-time PCR ( qRT-PCR) , and their correlation with clinical pathological paramelers of RSA patientswere analyzed.Serum anti-thyroid globulin antibodly (A-TC) and anti-thyroid peroxidase antibotdy ( A-TPO) were detected by the elec-trochemiluminescence assay.Serum anticardiolipin ( ACA) IgA, IgG , and IgM antibodies and anti-$2 glycoprotein 1 ( B2GP1) IgA,IgG, and lgM antibodties were determined by the chemiluminescence immunoassay. The corelation of these autoantilodlies with the lev-els of hsa_circ_0005075 in serum EVs was analyzed by the Pearson correlation.The clinical application value of hsa_cir._0005075 inthe diagnosis of RSA was evaluated by the receiver operating characteristic ( ROC) curve. Results The detection results of the trainingset showed that the expression levels of lhsa_circ_0005075 in serum EVs of RSA patients (7.69[4.74,42.15] ) were significantly high-er than that in normal pregnant women ( 1.02[ 0.51,4.23],U=28,P<0.01]. Similarly, in the validation set , the expression levels ofhsa_eirc_0005075 in RSA patients ( 4.96[1.73，8.89] ) were also significantly higher than that in normal pregnant women ( 1.00[0.24,2.96], U=693，P<0.01).The ROC curve showed that hsa_circ_0005075 in senum EVs had good diagnostic value for RSA(AUC RC=0.774)， with 70.3% of sensitivity and 75.0% of specificity . In addition , the expression level of hsa_circ_0005075 in serumEVs was significantly correlated with A-TPO (r=0.298，P<0.05 ).ConclusionThe hisa_circ_0005075 in serum EVs is highly ex-pressed in RSA patients，which may have a potential differential diagnostic value for the diagnosis of RSA.