Abstract: Objective To explore clinical factors influencing fetal growth restriction (FGR) in the first three months and its preventive measures.Methods A total of 56 pregnant women with FGR in our hospital from January 2013 to December 2014 were selected (FGR group).Meanwhile 56 normal full-term pregnant women were enrolled in the control group.A questionnaire was applied to investigate the common information of the pregnant.Height,weight and body mass index of pregnant women were measured and calculated.And blood pressure was measured and hematocrit and hemoglobin levels were detected.Fetal growth in the first three months was recorded.At the same,the effect of early pregnancy factors on crown-rump length was assessed by multivariate analysis.Also,fetal growth restriction for adverse birth outcomes was evaluated.Results Age,hematocrit,hemoglobin level,educational level,smoking,drinking,folic acid supplementation,the initial delivery,diastolic blood pressure of pregnant women in FGR group and control group showed significant difference (P ＜ 0.05).Crown-rump length,head circumference at birth,birth length,birth weight and gestational age in FGR group and the control group showed a significant difference (P ＜ 0.05).Maternal age,hematocrit,hemoglobin level,smoking (≥ 10 cigarettes daily) and folic acid supplementatior had a significant impact on fetal crown-rump length (P ＜ 0.05).First-trimester fetal growth restriction could increase risk of preterm birth,low birth weight,and low gestational age at birth.Conclusion High maternal age,low education level,high hematocrit and hemoglobin levels,smoking,drinking,lack of folic acid supplements,high diastolic blood pressure are risk factors for fetal growth restriction occurred in first-trimester.Trimester fetal growth restriction can adversely affect born fetus.Therefore,effective,comprehensive prevention and control measures should be taken during pregnancy to prevent theses risk factors.