537: Sonographic evaluation of fetal fractional limb volume across gestation in gestational diabetes

Abstract

Fractional limb volume has recently been proposed as a useful parameter of fetal growth, quantifying fetal soft tissue volume of upper arm and thigh. However, the investigation about the growth characteristics of fractional limb volume in mothers with gestational diabetes is limited. The aim of this study was to investigate the difference in growth trajectory of fractional arm volume and thigh volume between fetuses of gestational diabetes (GDM) and normal glucose tolerance (NGT) mothers. Fetal fractional limb volume was prospectively assessed in 158 singleton pregnancies (121 NGT and 37 GDM) between 20 and 37 weeks gestation. Fractional arm volume and thigh volume were measured as cylindrical limb volume based on 50% of humeral or femoral diaphysis length using a 5-slice technique. First, Student’s t-test was performed to compare fractional arm volume and thigh volume between NGT and GDM group across gestation. Multiple regression analyses were then performed to investigate the difference of fractional limb volume between NGT and GDM group, with adjustment for potential confounding factors (maternal age, parity, pregravid body mass index and fetal sex). Maternal and neonatal characteristics of each group are shown in Table 1. A total of 276 ultrasound scans were obtained, a mean of 1.7 scans (range: 1 - 4) per pregnancy. Fractional arm volume was not different between NGT and GDM group before 32 weeks gestation. However, fractional arm volume of GDM group was significantly larger than NGT group after 32 weeks gestation (Figure 1). These results remained significant even after controlling for the confounding factors. Fractional thigh volume was not statistically different between the two groups across gestation. Fetalfractional arm volume is significantly greater in women with GDM compared with NGT, particularly after 32 weeks gestation. This finding is consistent with the characteristic soft tissue accrual (including fat deposition) in the upper part of the fetal body in GDM, which possibly explains the higher occurrence of shoulder dystocia at delivery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)