Is fetal abdominal subcutaneous fat comparable with established indices of growth restriction?

The purpose of this study was to determine if measurement of the abdominal subcutaneous fat antenatally using ultrasound is comparable to other established indices of fetal growth restriction (FGR). One hundred women with singleton pregnancies had an ultrasound scan within 1 week of delivery at term. Ultrasound measurements included abdominal circumference (AC), liquor assessment by amniotic fluid index (AFI) and abdominal subcutaneous fat thickness (FAB). After delivery, infants were weighed and skinfold thickness at triceps and subscapular sites measured. Ponderal index was also calculated. Infants with an abdominal subcutaneous fat measurement antenatally of 5 mm or less (n=41) were more likely than those with a fat measurement of more than 5 mm (n=59) to have an AFI <8 cm (P<0.001) and to have an AC <10th centile (P<0.001). Decreased antenatal fat thickness was associated postnatally with a lower mean ponderal index (24.2 kg/m³ vs. 25.5 kg/m³, P<0.02) and a decreased skinfold thickness (4.84 vs. 5.55 mm, P<0.003 and 3.88 vs. 4.37, P<0.03 for triceps and subscapular, respectively). This study shows that fetal abdominal subcutaneous fat measurement correlates with established predictors of fetal nutrition such as liquor volume, abdominal circumference, ponderal index, triceps and subscapular skinfold thickness.