Predicting fetal growth restriction by humerus volume: A three-dimensional ultrasound study

Prenatal diagnosis of fetal growth restriction (FGR) is very important, as FGR may have increased risks with perinatal morbidity and mortality. Fetal humerus dysplasia is associated with a variety of congenital syndromes and FGR. For the assessment of the efficacy of fetal humerus volume in predicting FGR, we undertook a prospective cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 42 fetuses with FGR and 258 fetuses without FGR were included for the humerus volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to determine whether they were complicated with FGR or not. Our results revealed that fetal humerus volume assessed by 3D US can differentiate fetuses with FGR from fetuses without FGR well. The best predicting threshold for FGR is at the 10th percentile by humerus volume. Using the 10th percentile as the cutoff, the sensitivity of fetal humerus volume in predicting FGR was 97.6%, specificity 87.2%, positive predictive value 55.4%, negative predictive value 99.6% and accuracy 88.7%. In conclusion, fetal humerus volume assessed by quantitative 3D US can be used to predict FGR prenatally. We believe fetal humerus volume assessment by 3D US would be a useful test in detecting fetuses with FGR.