Predicting gestational diabetes: choosing the optimal early serum marker

OBJECTIVE: Serum markers measured early in pregnancy have been associated with the later diagnosis of gestational diabetes mellitus. To select an optimal early (<20 weeks) marker, we prospectively compared 3 serum markers examined simultaneously in a single cohort. STUDY DESIGN: A nested case-control design was used to evaluate the association of sex hormone-binding globulin, high-sensitive C-reactive protein, and measures of fasting glucose and insulin (homeostasis assessment model) obtained in the late first trimester and early second trimester of pregnancy with the diagnosis of gestational diabetes mellitus. Multivariate modeling and log likelihood ratios were used to identify the optimal biomarker associated with gestational diabetes mellitus. RESULTS: In both first and second trimester samples, sex hormone-binding globulin was lower and high-sensitive C-reactive protein higher among women who subsequently developed gestational diabetes mellitus. Similarly an elevated second-trimester homeostasis assessment model was associated with gestational diabetes mellitus. Multivariate analysis suggested that sex hormone-binding globulin measured from nonfasting first-trimester sera was the best predictor of gestational diabetes mellitus in our population. CONCLUSION: Among 3 biomarkers examined prospectively, first-trimester nonfasting sex hormone-binding globulin appeared to be the optimal marker to predict subsequent gestational diabetes mellitus.