Three-dimensional qualitative sonographic evaluation of fetal soft tissue

Even though fetal growth restriction and macrosomia remain as major problems currently facing obstetricians, there is still no modality for the assessment of fetal soft tissue deposition and muscle mass in utero. A total of 52 fetuses from 29 to 41 weeks gestation were studied within 1 week before delivery using a transabdominal three-dimensional (3D) transducer (3.5 MHz). Their birth weights varied from 1016 to 4018 g, and their crown-heel length from 37 to 54 cm. The amount of subcutaneous tissue was estimated using the fetal nutrition score. The fetal nutrition score values were determined from a qualitative assessment of the amount of subcutaneous tissue present at three locations (face, ribs and buttocks) on the antenatal 3D ultrasonograms. Fetal nutritional status, using fetal nutrition score, was compared with that found by modified neonatal nutrition score and ponderal index respectively. There was a significant linear correlation between fetal nutrition score and modified neonatal nutrition score. Fetal or neonatal nutrition score were strongly correlated with birth weight and neonatal crown-heel length. However, no significant correlation was found between ponderal index, fetal nutrition score, or modified neonatal nutrition score. Ponderal index also was not correlated with birth weight and neonatal crown-heel length. Moreover, fetal nutrition score was correlated with Apgar score, but not with umbilical cord arterial blood pH. Therefore, doubt is cast on the usefulness of the ponderal index for measurement of neonatal soft tissue and muscle mass. Fetal nutrition score using 3D ultrasonography provides a novel means of evaluating the nutritional status of the fetus in utero, and should be useful for predicting the extremes in fetal growth (fetal growth restriction and macrosomia) at an earlier stage than hitherto achieved.