Maternal serum placental growth hormone, insulin-like growth factors and their binding proteins at 20 weeks' gestation in pregnancies complicated by gestational diabetes mellitus.

OBJECTIVE: To investigate whether maternal serum concentrations of placental growth hormone (GH-V), insulin-like growth factor (IGF) 1 and 2, and IGF binding proteins (IGFBP) 1 and 3 were altered in pregnancies complicated by gestational diabetes mellitus (GDM).

METHOD: In a nested case-control study, GDM cases (n=28) and matched controls (n=28) were selected from the Screening for Pregnancy Endpoints (SCOPE) biobank in Auckland, New Zealand. Maternal serum hormone concentrations at 20 weeks of gestation were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS: There was no significant difference in maternal serum GH-V concentration in the GDM group compared to the control group (1.64 ± 0.11 ng/ml vs. 1.38 ± 0.10 ng/ml, p=0.079). However, GDM cases who delivered large for gestational age (LGA) babies had significantly higher serum GH-V concentrations compared to non-diabetic control cases. Maternal IGF-1 concentrations in GDM pregnancies were significantly higher than in controls (275.7 ± 11.5 ng/ml vs. 218.5 ± 11.1 ng/ml, p <0.001). Maternal IGFBP-1 concentrations were significantly lower in GDM pregnancies than in controls (41.04 ± 3.42 ng/ml vs. 67.58 ± 6.17 ng/ml, p <0.001). There were no significant differences in serum IGF-2 and IGFBP-3 concentrations between groups.

CONCLUSION: Concentrations of IGF-1 and IGFBP-1 in maternal serum were altered in GDM pregnancies compared to controls, suggesting that the IGF axis plays a role in the development of this condition. GH-V may be associated with macrosomia as increased maternal GH-V was observed in GDM cases who delivered LGA babies.