Sonographic measurement of the umbilical cord and fetal anthropometric parameters

Objective: To determine reference ranges for the diameter and the cross-sectional area of the umbilical cord during pregnancy and to determine if umbilical cord morphometry is related to fetal size. Methods: A prospective cross-sectional study was designed to assess the sonographic cross-sectional diameter and area of the umbilical cord. The sonographic umbilical cord measurements were obtained in a plane adjacent to the insertion of the cord into the fetal abdomen. Nomograms for the umbilical cord diameter and area were computed. Fetal biometry included: biparietal diameter, abdominal circumference, and femur length. Polynomial regression analysis was conducted. Results: Five hundred and fifty seven patients were included into the study. The regression equation for the umbilical cord diameter (y) according to gestational age (x) was y = -10.0563 + 1.4265x + 0.0194x(2) and for the umbilical cord area (y') was y' = 91.6-3.3x + 0.03x(2)-0.00007x(3). A significant relationship was found between umbilical cord measurements and fetal anthropometric parameters. Conclusion: Reference ranges for umbilical card diameter and area have been generated. The sonographic diameter and cross-sectional area of the umbilical cord increase as a function of gestational age and both diameter and area correlate with fetal size. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.