Low levels of Sex-Hormone-Binding Globulin predict insulin requirement in patients with gestational diabetes mellitus

Low Sex-Hormone-Binding Globulin (SHBG) levels indicating a state of hypera ndrogenicity - are associated with a higher risk for the development of non -insulin dependent diabetes (NIDDM) in women and are accepted as a marker o f muscular insulin resistance. To analyze whether low SHBG values are also present in patients with gestational diabetes, we investigated levels of SH BG in 42 patients with gestational diabetes mellitus (GDM) in comparison wi th 48 pregnant women with normal glucose tolerance (NGT). Beside maternal p arameters like body-mass index (BMI), HbA1c, fasting, 1- and 2-hour blood g lucose and insulin concentrations, parameters of the new-borns (head-circum ference, body weight, height and sex) were recorded. Maternal and neonatal variables were then related to SHBG levels. Both groups showed no differenc es in BMI, height, weight or age of gestation. Patients with GDM revealed s ignificantly lower levels of SHBG than pregnant women with NGT(512 +/- 249 nmol/l vs. 643 +/- 137 nmol/l: p < 0.01). In patients with severe GDM and i nsulin therapy significantly lower levels of SHBG than in those with dietar y treatment only were found (223 +/- 210 nmol/l vs. 592 +/- 102 nmol/l; p < 0.001). SHBG was inversely correlated to BMI (r = -0.30, p < 0.01), 1-hour (r= -0.20 p < 0.05) and 2-hour blood glucose levels (r = -0.30; p < 0.01). In summary, we found significantly lower levels of SHBG in patients with G DM, especially in those who developed severe GDM and required insulin thera py during the last months of pregnancy.