Fetal abdominal subcutaneous tissue thickness measured by ultrasound at term is associated with birth weight and mode of delivery

To determine if measurement of fetal abdominal subcutaneous tissue thickness (FASTT) at term can predict birth weight, mode of delivery and perinatal outcome. A prospective study with 352 normal, singleton pregnancies in the vertex presentation examined with real-time ultrasound at 37-39 weeks' gestation. FASTT was positively correlated with birth weight (Pearson's, r = 0.784, p < 0.001). Fetuses with low FASTT were more likely to be delivered through normal vaginal delivery (7.8 +/- 0.1 mm), while higher FASTT was correlated with operative vaginal delivery (7.9 +/- 0.2 mm) and cesarean section (8.6 +/- 0.3 mm) (ANOVA, p = 0.034). In contrast, FASTT was not correlated with intrapartum CTG, labor duration and Apgar scores. In normal pregnancies, FASTT at term is positively associated with birth weight. With increasing FASTT the likelihood of operative vaginal and cesarean delivery increases. FASTT is not associated with perinatal outcome.