Sex hormone-binding globulin concentrations before conception as a predictor for gestational diabetes in women with polycystic ovary syndrome

Low plasma sex hormone-binding globulin (SHBG) concentrations during pregnancy have been associated with the risk of developing gestational diabetes mellitus (GDM). Women presenting with polycystic ovary syndrome (PCOS) often exhibit low plasma SHBG concentration and are at increased risk of developing GDM. In this study, we investigate whether SHBG levels before conception are predictive of GDM in women with PCOS. A total of 50 women with PCOS were enrolled and followed up during pregnancy. Initial endocrine, metabolic and physical features were assessed according to a standardized preconception screening program. At 24-26 weeks of gestational age a 100-g glucose tolerance test was performed to screen for GDM. Of the 50 women, 21 (42%) were diagnosed with GDM by a 100-g glucose tolerance test. Waist circumference, BMI, blood pressure, plasma glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and SHBG levels before conception were significantly different between women who did and did not develop GDM. Stepwise logistic regression analysis showed that SHBG was the most significant predictive parameter for GDM (odds ratio 0.92; 95% confidence interval 0.87-0.97), without significant contribution of waist circumference and HOMA-IR. Receiver operator characteristic (ROC) analysis indicated that plasma SHBG (area under the curve 0.86) had the highest predictive value for subsequent development of GDM, however, the limited group size did not allow for calculation of a threshold value of SHBG. In women with PCOS, preconception SHBG levels are strongly associated with subsequent development of GDM. Regression and ROC analysis show that preconception SHBG levels may be a better predictor for GDM in PCOS women compared with waist circumference or HOMA-IR. Clinical trial registration number: NCT00821379.