Effect of fetal macrosomia on human placental glucose transport and utilization in insulin-treated gestational diabetes.

The aim of this study was to compare glucose transport and utilization in human placentae from pregnancies affected by insulin-treated GDM with and without macrosomia, and from non-diabetic control pregnancies. Placental lobules were perfused for 4 h. Maternal D-glucose concentration was 4, 8, 16, or 24 mM while the fetal D-glucose was maintained at 3mM. 14C-D-glucose and 3H-L-glucose were infused into the maternal circulation. Radioactivity, D-glucose and L-lactate levels were measured in the fetal and maternal effluent perfusates. Glucose uptake from the maternal perfusate, and transfer to the fetal effluent were not significantly different between groups. Insulin-treated GDM group without macrosomia had reduced glucose utilization compared to the control group while the insulin-treated GDM group with macrosomia did not. Lactate release into the fetal effluent was significantly reduced in both insulin-treated GDM groups compared to the control group. In conclusion, placental glucose utilization is different between insulin-treated GDM placentae with and without fetal macrosomia.