Objective To study the differences of coagulation indices on the first day of birth in newborns with different gestational ages.Method Premature infants born in our hospital between January 2014 and December 2015 were enrolled in this study as the observational group,and they were divided into early preterm group,moderate preterm group,and late preterm group according to their gestational ages.Healthy full-term infants born during the same period were selected as the control group by 3:1 The clinicaldata and coagulation indices of the infants and their mothers in each group were compared.Result There were 44,50,71,and 52 cases in the early preterm,moderate preterm,late preterm,and control group,respectively.The prothrombin time (PT),activated partial thromboplastin time (APTT),and thrombin time (TT) of the premature infants in the early preterm group,moderate preterm group,and late preterm group were all longer than those of the control group [PT:(16.1 ±4.3) s,(16.8 ±4.9) s,(15.8 ±4.8) s,vs.(13.0±1.3)s;APTT:(88.3±38.1) s,(93.5±37.7) s,(91.0±32.3) s,vs.(66.0±17.8) s;TT:(25.4 ±4.6) s,(25.1 ±5.5) s,(25.0 ±3.3) s,vs.(24.0 ±3.3) s;all P＜0.05].The fibrinogen level of the premature newborns in three groups were all lower than that of the full-term infants in the control group [(1.11 ± 0.46) g/L,(1.12 ± 0.44) g/L,(1.12 ± 0.45) g/L vs.(1.28 ± 0.37) g/L,P ＜ 0.05].The differences of all the indices among the three groups of premature infants were all not statistically significant (P ＞ 0.05).The comparison of the coagulation indices of the mothers of the newborns from all four groups showed no significant differences (P ＞ 0.05).Conclusion Compared with full-term infants,preterm infants showed significantly poorer coagulation function on the first day of birth.However,there were no significant differences in coagulation indices among preterm infants of different gestational ages.