Abstract: Objective： To explore the relationship between the result of protecting fetus from late threatened abortion and blood leukocytes，neutrophils and the C-reactive protein（CRP）. Methods：A total of 227 patients with late threatened abortion to protect the fetus，from April 2012 to March 2013 in Dalian Obstetrics and Gynecology Hospital，were performed routine blood and CRP examination，subjects were divided into two groups，181 of them protected the fetus successfully with the success rate 79.7%，and 46 cases resulted in inevitable abortion，with the rate 20.3%. And relationship of the blood leukocyte，neutrophil percentage，neutrophils absolute value，and CRP between the two groups were analyzed. Results：Compared with the inevitable abortion group and successfully protected the fetus group，their blood WBC，neutrophil percentage，neutrophils absolute value and CRP were found with statistically difference（P＜0.05）. The successfully protected the fetus group showed an negative correlation with CRP，white blood cell and neutrophil absolute value，while the inevitable abortion and the percentage of neutrophils was positively correlated（P＜0.05）. By ROC curve analysis to predict the inevitable abortion with WBC，neutrophil percentage，neutrophils absolute value and CRP，the area under the curve were calculated to be 0.881，0.800，0.800，0.779，the sensitivity to be 87.0%，76.1%，71.7% and 73.9%，and the specific degree 75.7%，76.2%，69.6% and 81.2% respectively. Conclusions：A certain correlation existed between the risk of late threatened abortion and infection，and blood cells，neutrophils and CRP have moderate predictive value for late inevitable abortion，which provide a certain basis for clinical treatment.

Key words: Abortion, threatened, Leukocytes, Neutrophils, C-reactive protein