Objective To study the relationship between intrauterine infection and early neonatal sepsis.Method From October 2015 to September 2016,the clinical data of pregnant mothers and their newborns in Shenzhen Longhua District Central Hospital were collected,and data of Shenzhen People's Hospital from January 2016 to June 2016 were collected.100 pairs of pregnant mothers and their newborns with confirmed or suspected intrauterine infection were selected as the observation group,and another 100 pairs without intrauterine infection during the same period as the control group.The ratio of term infants vs.premature infants was 1∶ 1.The complete blood count (CBC),CD64,procalcitonin (PCT) and C-reactive protein (CRP) were measured in peripheral blood of all mothers on the day of delivery.The CBC,CD64,CRP,PCT,blood culture of both umbilical venous blood and peripheral blood in neonates were examined and the pathological examination of placenta was performed.Result The positive rate of placental pathology and umbilical cord blood culture in observation group were significantly higher than that in the control and the positive rate in preterms was higher than the terms in observation group (P ＜ 0.05).No significant differences existed between term and premature newborns on the positive rate of peripheral blood culture (P ＞ 0.05).The positive rate of blood culture from umbilical cord blood was higher than peripheral blood in observation group (P ＜ 0.05),but no significant difference in control group (P ＞ 0.05).The incidence of septicemia in term and premature newborns in observation group was significantly higher than the control group (P＜ 0.05).The CD64,PCT in mother's peripheral blood and umbilical cord blood,and CRP in mother's blood were all higher than the control group,the differences were statistically significant (P ＜ 0.05),but CRP in umbilical cord blood in both group were similar (P ＞ 0.05).The area under ROC curve of CD64 and PCT in mother's peripheral blood,CD64 and PCT in umbilical cord blood to diagnose early-onset septicemia in newborns was 0.755,0.793,0.852 and 0.811,respectively.Conclusion The risk of neonatal infections is significantly increased because of intrauterine infection.Combination of peripheral and umbilical blood cultures can increase the accuracy of sepsis diagnosis.Both CD64 and PCT in umbilical cord blood and maternal blood can be used as indicators of intrauterine infection with a predictive value in the diagnosis of early-onset neonatal sepsis.