Sex hormone binding globulin measurement before conception as a predictor of gestational diabetes in women with polycystic ovarian syndrome

BACKGROUND The objective of this study was to investigate whether the sex hormone binding globulin (SHBG) levels before conception are predictive of gestational diabetes mellitus (GDM) in women with polycystic ovarian syndrome (PCOS). MATERIALS AND METHODS A total of 180 women with PCOS were enrolled and followed up during pregnancy. Diagnosis of GDM was based on a 2-hour, 75 g oral glucose tolerance test (GTT) performed at 24-28 weeks of gestational age. SHBG levels were measured from serum samples that had collected before conception. We examined the incidence of GDM and plotted a receiver operating characteristic (ROC) curve to assess discrimination. RESULTS Of the 180 women, 50 (27.8%) were diagnosed with GDM. Those with lower levels of SHBG before conception were more likely to develop GDM than those with higher SHBG (44.4 ± 14.8 nmol/l vs. 63.5 ± 22.7 nmol/l, P < 0.001). The area under the ROC was 77.0% (95% confidence interval [CI] 71.3-78.8). The optimal cut-off value for detecting GDM was a SHBG ≥62.5 nmol/l. For every 1 nmol/l increase in SHBG value, there was a 7% reduction in the risk for development of GDM (Odds ratio 0.93 [95% CI 0.90-0.96], P < 0.001). CONCLUSION In women with PCOS preconception, SHBG levels are strongly associated with development of GDM.