Association between gestational diabetes mellitus and bioavailability of insulin-like growth factors and role of their binding proteins

Objective: Insulin-like growth factors (IGFs) are involved in regulating growth and metabolism and increase in-sulin sensitivity, improve glucose metabolism, and are potentially related to gestational diabetes mellitus (GDM) and its complications for mothers and fetuses.Design: This study aimed to assess serum levels and cord blood levels of IGF system components in pregnant women with (39 participants) and without GDM (22 participants). Blood samples were obtained at 28-32 and 36-38 weeks of gestation and 6-12 months after delivery. Cord blood samples were obtained during delivery. Results between both groups as well as between single visits were statistically compared.Results: Both IGF1 and IGF2 maternal serum levels did not differ between the GDM and non-GDM groups. However, levels of IGF-binding proteins (IGFBPs) were different. IGFBP4 levels were decreased during pregnancy and after delivery in women with GDM, while IGFBP7 levels were increased during pregnancy in women with GDM. Cord blood IGFBP3 and IGFBP7 levels were increased (p < 0.001 for IGFBP3, p = 0.003 for IGFBP7), while IGFBP4 levels were decreased (p < 0.001) in the GDM group compared with the non-GDM group. Conclusions: Although IGF levels did not differ, changes in their function level could still persist possibly because of the effects of the binding proteins, especially their promoting or inhibitory effects on IGFs. These results should be considered in interpretation of IGF levels.

Automated summary

This study investigated the levels of insulin-like growth factors (IGFs) and their binding proteins in pregnant women with and without gestational diabetes mellitus (GDM). The results showed that there were no differences in the levels of IGFs between the GDM and non-GDM groups, but the levels of binding proteins IGFBP4 and IGFBP7 had different patterns of change. Additionally, cord blood levels of IGFBP3 and IGFBP7 were increased, while IGFBP4 levels were decreased in the GDM group compared to the non-GDM group.