Sonographic determination of first trimester umbilical cord length.

Umbilical cord length was measured sonographically in 53 normal fetuses and 15 fetuses with an intrauterine demise. The age of the fetuses ranged from 6.1 weeks to 11 weeks, menstrual age. Intra- and interobserver differences in measurements were not significantly different from zero. A close linear relationship (r2 = 0.89) was found between umbilical cord length and menstrual age in the normal group. The cord lengths of 9 of 15 fetuses (60%) with an intrauterine fetal demise were more than 2 SD below the expected value for menstrual age in normal fetuses.