First-trimester sonographic umbilical cord diameter and the growth of the human embryo.

Objectives: Experimental and clinical evidence have shown that the morphometry of the umbilical cord in the second half of gestation might be useful in predicting adverse perinatal outcome. The purposes of this study were to generate a nomogram for the umbilical cord diameter in the first trimester and, in an observational study, to investigate whether the sonographic measurement of the umbilical cord diameter early in gestation has the same clinical value as that late in gestation.
Methods: The sonographic umbilical cord diameter, crown-rump length and biparietal diameter were measured in 439 fetuses at between 8 and 15 weeks of gestation. The perinatal outcome was recorded for all patients.
Results: The umbilical cord diameter increased steadily from 8 to 15 weeks of gestation. A significant correlation was found between umbilical cord diameter and gestational age (r = 0.78; P < 0.001), umbilical cord diameter and crown-rump length (r = 0.75; P < 0.001) and umbilical cord diameter and biparietal diameter (r = 0.81; P < 0.001). No correlation was found between umbilical cord diameter values and either birth weight or placental weight. Among patients who had a miscarriage (n = 7) and pre-eclampsia (n = 8) the umbilical cord diameter was below 2 standard deviations from the mean in three cases (42.9%) and three cases (37.5%), respectively.
Conclusion: The measurement of the umbilical cord diameter in the first trimester is correlated with the growth of the embryo and may be a marker for identifying a subset of fetuses at risk of spontaneous miscarriage and pre-eclampsia.