The relationship between maternal serum iron and zinc levels and their nutritional intakes in early pregnancy with gestational diabetes.

The aim of this study was to investigate the association between maternal iron/zinc serum levels and their nutritional intake in early pregnancy with gestational diabetes. The maternal serum zinc/iron levels were measured in 1,033 healthy singleton pregnant women aged 20-35 between 14 and 20 weeks of gestation, within two groups: namely, normal and gestational diabetes, and participants were followed up to 24-28 weeks of gestation. Food frequency questionnaire was used to assess nutritional intakes of iron/zinc. The main outcome was gestational diabetes screened with the 50-g glucose challenge test and diagnosed with oral glucose tolerance test at 24-28 weeks of gestation. Gestational diabetes occurred in 72 (6.96 %) of 1,033 women in study. There was a statistical relationship between early pregnancy maternal serum iron and gestational diabetes, mean (SD), 143.8 (48.7) vs. 112.5 (83.5) μg/dl, P value of <0.0001. There was no statistical significant difference in zinc levels and iron/zinc nutritional intake between groups. The results remained unchanged after using regression model for adjustment of potential risk factors with an adjusted OR of 1.006 (95 % CI 1.002 to 1.009; P = 0.001) for early pregnancy maternal serum iron to cause gestational diabetes. The receiver-operator characteristic curve identified that a maternal serum iron above 100 μg/dl in early pregnancy is the optimum cutoff value for predicting gestational diabetes, which showed a sensitivity and specificity of 80.6 and 50.7 %, respectively. In conclusion, high maternal serum iron in early pregnancy could increase the risk of gestational diabetes. Also, it could be used as a sensitive and specific predictor for gestational diabetes.