Sex hormone binding globulin as a valuable biochemical marker in predicting gestational diabetes mellitus

BACKGROUND Circulating Sex hormone binding globulin (SHBG) levels are inversely associated with insulin resistance. This study was conducted to compare maternal serum SHBG level between pregnant women with normal glucose tolerance and those with gestational diabetes (GDM) and to investigate the roll of SHBG in GDM diagnosis. METHODS This was a case controlled study of 90 pregnant women, 45 women with GDM and 45 matched controls, attending obstetrics clinic at Ohud Hospital, Madina, Saudi Arabia between April 2014 and March 2015. Measurement of serum SHBG levels by Enzyme-linked immunosorbent assay (ELISA) method were done between 24 and 28 weeks of gestation. The best cut-off point of SHBG to diagnose GDM was calculated in receiver operating characteristic curve. RESULTS Compared with the control group, SHBG concentrations were significantly lower in the GDM group; median 23 nmol/L (18-30) vs. 78 nmol/L (65-96), p < 0.001). The cut off value 50 nmol/L of the SHBG had 90% sensitivity and 96% specificity to diagnose GDM. CONCLUSION Patients with GDM have lower circulating levels of SHBG than normal glucose tolerance pregnant women. Circulating concentrations of SHBG represent a potentially useful new biomarker for prediction of risk of GDM beyond the currently established clinical and demographic risk factors.