Ultrasound evaluation of fetal spine length between 14 and 24 weeks of gestation

The objective of our study was to establish a nomogram of fetal spine lengt h in the second trimester of pregnancy by using two and three-dimensional u ltrasound. Fetal spine length was measured prospectively by means of transa bdominal ultrasonography in 114 normal singleton pregnancies between 14 and 24 weeks of gestation. Regression analyses were performed on spine length, gestational age, biparietal diameter and femur length. Supplementary three -dimensional ultrasound to assess fetal spine length was performed in 75 ca ses. Fetal spine length, as a function of gestational age, was expressed by the following regression equation: spine length (mm)= - 47.2+ 7.16 x gesta tional age (weeks), with a Pearson correlation coefficient of R-2=0.956. Th e results of the measurements revealed no difference between two and three- dimensional ultrasound. Our study defines the normal limits of fetal spinal length in the second trimester of pregnancy and demonstrates a high correl ation between spinal length, gestational age, biparietal diameter and femur length. However, there are still too few prenatal research data to say whe ther and to what extent an assessment of fetal spine length at this stage o f pregnancy can be used for prenatal diagnosis of congenital syndromes, whi ch, among other manifestations, are marked by fetal spine lengthening or sh ortening. Copyright (C) 1999 John Wiley & Sons, Ltd.