Objective To explore the application value of fractional limb volume obtained by three-dimensional（3 D）ultrasound in predicting late-onset fetal growth restriction（FGR） at 23～24 weeks of gestation.Methods A total of 74 pregnant women diagnosed with late-onset FGR in our hospital were selected as the case group

and 200 normal pregnant women were included as the control group.Measurements were performed at 23～24 weeks of gestation by two-dimensional ultrasound for standard fetal biometry

biparietal diameter

head circumference

abdominal circumference

femur length and ultrasoundestimated fetal weights（EFW1）

3 D ultrasound for fractional arm volume on 50% of the humeral diaphysis length（AVol） and fractional thigh volume on 50% of the femoral diaphysis length（TVol）

EFW2 or EFW3 were obtained by EFW1 combined with AVol or TVol.The value of the parameters in predicting the late-onset FGR was analyzed by ROC curve.Results There were no significant differences in terms of biparietal diameter

head circumference

abdominal circumference

femur length and EFW1

EFW2

EFW3.There were significant differences in AVol and TVol between the two groups（both P<0.05）.ROC curve analysis showed that the area under ROC curve in predicting by AVol and TVol for late-onset FGR were 0.70 and 0.74

respectively

and there was no significant differences between groups.The cut-off values were 4.5 ml and 9.4 ml

respectively.The sensitivity

specificity and accuracy for predicting late-onset FGR of the two groups were 63.5% and 69.4%

89.4% and88.1%

81.4% and 83.2%

respectively.The sensitivity

specificity and accuracy in combined prediction of late-onset FGR were79.0%

94.8% and 90.1%

respectively.Conclusion AVol and TVol can be used as the specific indicators in predicting lateonset FGR at 23～24 weeks of gestation.