Abstract: Objective To explore the relationship between serum mircoRNA-210(miR-210) and the severity and prognosis of neonatal respiratory distress syndrome（NRDS）. 
Methods A total of 104 children with NRDS were selected and divided into survival group and death group according to the prognosis of the children. All newborns were divided into mild group(grade Ⅰ, Ⅱ) and severe group(grade Ⅲ, Ⅳ) according to the results of the first chest radiograph and the severity of the disease. The general data of the children in the death group and the survival group were compared, and the serum miR-210 level and the scores for neonatalacute physiology and perinatal extension Ⅱ(SNAPPE-Ⅱ) of the mild group and the severe group were compared. The receiver operating characteristic(ROC) curve was drawn to analyze the value of serum miR-210 level in predicting the death of children with NRDS. Spearman correlation was used to analyze the correlation between the occurrence of NRDS and serum miR-210. 
Results According to grouping by prognosis, among the 104 cases, 81 cases(77.88%) had good prognosis, and 23 cases(22.12%) died. The level of miR-210 and SNAPPE-Ⅱ in the survival group were lower than those in the death group(P＜0.05). There was no significant difference in gender, gestational age, birth weight, maternal age, etiology, cesarean section, twin pregnancy, and abnormal amniotic fluid between two groups(P＞0.05). According to the chest X-ray findings, 73 of the 104 children were mild and 31 were severe. The level of miR-210 and SNAPPE-Ⅱin the mild group were lower than those in the severe group(P＜0.05). The occurrence of NRDS was positively correlated with the level of serum miR-210(r=0.638, P＜0.001). Serum miR-210 was positively correlated with SNAPPE-Ⅱ(r=0.513, P＜0.05). When the optimal cut-off value of serum miR-210 was 16.71 ng/L,the area under the ROC curve was 0.763(OR=0.846, 95%CI:0.892-1.064), the sensitivity was 82.61%, and the specificity was 86.42%. 
Conclusion The increase in serum miR-210 level is closely related to the severity and prognosis of NRDS, and the serum miR-210 level is positively correlated with the severity of NRDS. When the cut-off value of serum miR-210 is 16.71 ng/L, it is of higher value in assessing the prognosis of children with NRDS. 

Key words: respiratory distress syndrome, newborn, microRNA, prognosis