Fetal upper arm volume in predicting intrauterine growth restriction: a three-dimensional ultrasound study.

As fetuses with intrauterine growth restriction (IUGR) may have increased risks with perinatal morbidity and mortality, prenatal diagnosis of IUGR is a very important issue in perinatology. To assess the efficacy of fetal upper arm volume in predicting IUGR, we undertook a prospective, cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 40 fetuses with IUGR and 442 fetuses without IUGR were included for the upper arm volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to establish whether they were complicated with IUGR or not. Our results showed that fetal upper arm volume assessed by 3D US can differentiate fetuses with IUGR from fetuses without IUGR well. The best predicting threshold for IUGR is at the 10th percentile by upper arm volume. Using the 10th percentile as the cutoff, the sensitivity of fetal upper arm volume in predicting IUGR was 97.5%, with specificity 92.8%, predictive value of positive test 54.9%, predictive value of negative test 99.8% and accuracy 93.1%. Furthermore, upper arm volume is the best parameter for detecting IUGR among the common fetal biometric indices, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW). In conclusion, fetal upper arm volume assessed by quantitative 3D US can be used to predict fetuses with IUGR antenatally. We believe fetal upper arm volume assessment by 3D US would be a useful test in detecting fetuses with IUGR.