Vitamin D status during pregnancy and the risk of gestational diabetes mellitus: A longitudinal study in a multiracial cohort

Diabetes Obes Metab. 2019 Aug;21(8):1895-1905. doi: 10.1111/dom.13748. Epub 2019 May 14.


Aim: To prospectively and longitudinally investigate vitamin D status during early to mid-pregnancy in relation to gestational diabetes mellitus (GDM) risk.

Methods: In a nested case-control study of 107 GDM cases and 214 controls within the Fetal Growth Studies-Singleton Cohort, plasma levels of 25-hydroxyvitamin D2 and D3 (25(OH)D) and vitamin D binding protein were measured at gestational weeks 10 to 14, 15 to 26, 23 to 31, and 33 to 39; we further calculated total, free, and bioavailable 25(OH)D. Conditional logistic regression models and linear mixed-effects models were used.

Results: We observed a threshold effect for the relation of vitamin D biomarkers with GDM risk. Vitamin D deficiency (<50 nmol/L) at 10 to 14 gestational weeks was associated with a 2.82-fold increased risk for GDM [odds ratio (OR) = 2.82, 95% confidence interval (CI): 1.15-6.93]. Women with persistent vitamin D deficiency at 10 to 14 and 15 to 26 weeks of gestation had a 4.46-fold elevated risk for GDM compared with women persistently non-deficient (OR = 4.46, 95% CI: 1.15-17.3).

Conclusions: Maternal vitamin D deficiency as early as the first trimester of pregnancy was associated with an elevated risk of GDM. The association was stronger for women who were persistently deficient through the second trimester. Assessment of vitamin D status in early pregnancy may be clinically important and valuable for improving risk stratification and developing effective interventions for the primary prevention of GDM.

Keywords: observational study; population study.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 25-Hydroxyvitamin D 2 / blood
  • Adult
  • Calcifediol / blood
  • Case-Control Studies
  • Diabetes, Gestational / epidemiology
  • Diabetes, Gestational / ethnology
  • Diabetes, Gestational / etiology*
  • Female
  • Humans
  • Logistic Models
  • Longitudinal Studies
  • Odds Ratio
  • Pregnancy
  • Pregnancy Complications / blood*
  • Pregnancy Complications / ethnology
  • Pregnancy Complications / etiology
  • Pregnancy Trimester, First / blood
  • Risk Factors
  • Vitamin D Deficiency / blood*
  • Vitamin D Deficiency / complications
  • Vitamin D Deficiency / ethnology
  • Vitamin D-Binding Protein / blood
  • Young Adult


  • GC, vitamin D binding protein, human
  • Vitamin D-Binding Protein
  • 25-Hydroxyvitamin D 2
  • Calcifediol