Growth of fetal lean and fat mass in gestational diabetes

OBJECTIVES: This study was carried out to investigate growth indicators of fetal lean mass and fat mass in the second half of the gestational period in pregnancies complicated by gestational diabetes mellitus (GDM) in comparison to normal control pregnancies. METHODS: Forty-three control and 171 GDM pregnancies were followed longitudinally by ultrasound examinations, measuring both traditional biometric parameters and six non-traditional parameters for the evaluation of lean and fat mass. A mixed linear model derived from the log-Count function was used to model fetal growth and to make comparisons between groups. Factor analysis was used to evaluate the associations between gestational diabetes and fetal size and fetal fat/lean mass ratios. RESULTS: A total of 506 scans were obtained in the 214 pregnancies, a mean of 2.4 scans per pregnancy (range 2-5). Maternal age, prepregnancy weight and body mass index were significantly higher in GDM pregnancies. Fetuses of GDM pregnancies showed greater growth, at the same gestational age, for each lean and fat non-traditional parameter, having a significantly greater amount of total tissue mass and a higher fat mass/lean mass ratio, independent of gestational age, in comparison to control pregnancies. CONCLUSIONS: A non-invasive, repeatable evaluation of fetal body composition in utero could represent a useful method for the early detection of growth abnormalities and for direct estimation of the fetal metabolic status.