Prenatal ultrasonographic assessment of Wharton's jelly: Relationship with fetal growth parameters and funic indices in normal pregnancy

Background: This study was designed to test the hypothesis that the amount of Wharton's jelly (WJ) is correlated with the increment in gestational age (GA) and with common fetal somatic growth parameters as well as with umbilical cord indices in normal pregnancy. Materials and Methods: A prospective cross-sectional study to assess WJ by ultrasound was set up at the Antenatal Ultrasound Unit of the National Cheng-Kung University Hospital. The ultrasound measurements taken included biparietal diameter (BPD), occipito-frontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL), umbilical artery diameter (UAD), umbilical vein diameter (UVD) and umbilical cord diameter (UCD). From UAD, UVD and UCD, the umbilical artery area (UAA), umbilical vein area (UVA), umbilical cord area (UCA) and WJ were calculated. Ultrasound measurements were taken between 16 and 40 weeks' gestation. All subjects were followed until their delivery to ensure that the babies were normal and of appropriate size for GA. Results: A total of 984 normal singletons with a GA ranging from 19 to 32 weeks were included for analysis. The amount of WJ correlated significantly with GA and with all fetal somatic growth indices, ie, BPD, OFD, HC, AC and FL (all p < 0.0001). In addition, the amount of WJ correlated significantly with UVD (p = 0.0088), UCD (p < 0.0001) and UCA (P < 0.0001). From a multivariate analysis, four variables, ie, UVD, UCA, FL and UCD, were found to be significant and they explained 94.94% of the variation of WJ (standard error = 0.10240, F-ratio = 4593, p < 0.0001). Conclusion: The increment in WJ correlated well with the advance of GA, fetal somatic growth parameters and some funic indices. These data may be used to serve as a basic reference for the prenatal detection of funic abnormalities.