Serum ferritin concentration in early pregnancy and risk of subsequent development of gestational diabetes: A prospective study

Background: Elevated serum ferritin concentration is associated with insulin resistance and diabetes. Recently it has also been described in gestational diabetes mellitus (GDM).
Objective: A prospective study was done to determine whether there was a relationship between serum ferritin concentration in early pregnancy and the risk of GDM.
Materials and Methods: A study was performed on 1,384 pregnant women with gestational age of 12-16 weeks. A blood sample was obtained for measurement of ferritin in the first trimester. Diagnosis of GDM was done by 75 gr oral glucose tolerance test between 24-28 wk.
Results: Women who developed GDM had a higher concentration of serum ferritin than women who did not develop GDM (p=0.01). A ferritin concentration of 45 ng/ml was calculated to be the 75^th percentile for healthy pregnant women. Considering this level 32% in the GDM group and 25.2% of normal subjects exhibited high ferritin levels (p=0.01). The risk of GDM with these high levels of ferritin was 1.4-fold higher than that for subjects with lower concentrations. The Odds Ratio was 1.4 (95% CI= 1-1.87) (p=0.01). After adjusted for age Odds Ratio was 1.38 (95% CI=1.02-1.86) (p=0.03) and after adjustment for pre-pregnancy Body Mass index, the adjusted odds ratio was 1.31 (CI= 0.96-1.79) (p=0.08). After multivariable adjustment (age and body mass index), the adjusted odds ratio was 1.3 (0.95-1.8) (p=0.09).
Conclusion: High serum ferritin can be regarded as a significant risk factor for the development of gestational diabetes.