Nomogram of Wharton's jelly as depicted in the sonographic cross section of the umbilical cord

Objectives To generate a nomogram for the sonographic measurement of Wharto n's jelly area (WJA) during gestation and to investigate whether WJA is rel ated to fetal biometric parameters. Method The sonographic cross-sectional area of the umbilical cord and of it s vessels was measured in 659 fetuses between 15 and 42 weeks of gestation. The WJA was calculated by subtracting the vascular area from the umbilical cord area. The conventional biometric parameters were measured and correla ted with the WJA. Polynomial regression analysis was utilized for statistic al purposes. Results The WJA increased as a function of gestational age (r = 0.63, P < 0 .001). The regression equation for the mean WJA (y) according to gestationa l age (x) was y = -114.7 + 4.142x - 0.01x(2) and for the standard deviation (y') was y'= -7.567 + 1.319x. There was a strong correlation between the W JA and the umbilical cord area (r = 0.97, P < 0.001). A significant correla tion was also found between the WJA and fetal biometric parameters before 3 2 weeks of gestation (WJA and biparietal diameter: r = 0.82, P < 0.001; WJA and abdominal circumference: r = 0.79, P < 0.001; WJA and femur length: r = 0.81, P < 0.001) while after 32 weeks of gestation no correlations were f ound between WJA and fetal anthropometric parameters. Conclusion A nomogram for the WJA bas been generated. The WJA increases as a function of gestational age and it is correlated with fetal size up to 32 weeks of gestation.