Sex hormone-binding globulin levels and obesity in women with gestational diabetes: relationship with infant birthweight

Abstract

Our objective was to determine whether sex hormone-binding globulin (SHBG) concentrations are associated with gestational diabetes mellitus (GDM) and whether this association is independent of prepregnancy body mass index (BMI). The relationship between maternal SHBG concentrations and birthweight in the offspring was also examined. The study included 47 women (20 with GDM, 27 controls). GDM screening and fasting serum SHBG measurements were performed at 26.1 ± 3.7 weeks of pregnancy. A trend was observed for significantly lower SHBG concentrations in GDM patients (179 ± 36 vs. 195 ± 36 nmol/l, p ≤ 0.08). Prepregnancy BMI and BMI at the time of GDM screening were both correlated with SHBG concentrations (r = −0.49 and r = −0.53, respectively; p  ≤ 0.001). In multivariate regression analyses, only prepregnancy BMI or BMI at the time of GDM screening remained significant predictors of GDM risk [odds ratio (OR):1.23, 95% confidence interval (CI):1.06–1.47, p  ≤ 0.01 and OR:1.18, 95% CI:1.02–1.39, p  ≤ 0.02] while SHBG level did not. On the other hand, 10.7% of the variance in birthweight was explained by SHBG concentrations (p  ≤ 0.01) independent of the presence of GDM, parity, maternal age, maternal prepregnancy BMI, maternal height, and offspring sex. In conclusion, although SHBG concentration is not an independent predictor of GDM risk when obesity is considered, it is a significant predictor of infant birthweight independent of GDM and prepregnancy BMI.

Keywords:

• SHBG
• pregnancy
• obesity
• glucose intolerance
• birthweight

Acknowledgments

Anne-Sophie Morisset is the recipient of a Canada Graduate Scholarships Doctoral Award from the Canadian Institute of Health Research. André Tchernof is the recipient of a senior scholarship from the Fonds de la Recherche en santé du Québec (FRSQ). Julie Robitaille is the recipient of a Junior Investigator scholarship from the FRSQ. The authors thank all participants of the study and acknowledge the support from the Laval University Medical Center Foundation and the late André Nadeau MD.

Declaration of interest:

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.