Compared with the highest quartile of SHBG concentrations , the odds of GDM increased with decreasing quartile ( odds ratio 1.06 [ 95 % CI 0.44-2 .52 ] ; 2.33 [ 1.07-5 .09 ] ; 4.06 [ 1.90-8 .65 ] ; P for trend < 0.001 ) , after adjusting for family history of diabetes , prepregnancy BMI , race/ethnicity , alcohol use , prepregnancy weight changes , and homeostasis model assessment of insulin resistance .