Influence of iron metabolism indices on HbA1c in non-diabetic pregnant women with and without iron-deficiency anemia: effect of iron supplementation

Diabetes Metab Syndr. Apr-Jun 2012;6(2):102-5. doi: 10.1016/j.dsx.2012.05.011. Epub 2012 Jun 28.


Aims: Condition that influence erythrocyte turnover also affect HbA1c. Although many forms of anemia are associated with lowering of HbA1c, iron-deficiency anemia (IDA) tends to increase HbA1c. In this study, we examined the relationship between HbA1c and erythrocyte indices in non-diabetic pregnancy and assessed the effect of iron supplementation on HbA1c.

Materials and methods: 150 women were studied (30 non-diabetic), non-pregnant, non-anemic women in child bearing women with varying parity as controls (Gp 1); 30 non-diabetic, non-anemic pregnant women in first trimester of pregnancy (Gp 2a); 30 non-diabetic, non-anemic pregnant women in second trimester of pregnancy (Gp 2b); 30 non-diabetic, non-anemic pregnant women in third trimester of pregnancy (Gp 2c) and 30 non-diabetic pregnant women with IDA (Gp 2d). HbA1c, OGTT, erythrocyte indices and iron metabolic indices were determined in Gp 2d subjects not supplemented with iron and repeated these indices after 3 months of iron-supplementation.

Results: The mean fasting and postprandial blood glucose levels (79.9±8.0mg/dl, 108.1±14.1mg/dl) in Gp 1 were found to be significantly lower in first trimester among Gp 2a (74.4±5.3mg/dl and 97.2±11.1mg/dl), in second trimester among Gp 2b (76.2±5.2mg/dl and 103.4±7.9mg/dl) followed by increase in IIIrd trimester among Gp 2c (82.3±5.7mg/dl and 112.5±8.5mg/dl) subjects. A significant difference in HbA1c was also observed among the groups (HbA1c 4.7±0.3% in Gp 1; 4.6±0.4% in Gp 2a; 4.5±0.3 in Gp 2b; 4.7±0.3 in Gp 2c). Among Gp 2d subjects, HbA1c was 5.2±0.3% and the level decreased after iron supplementation to 5.1±0.3%. Significant correlation between erythrocyte indices, iron metabolic indices and HbA1c was also observed.

Conclusion: We conclude that consideration should be given for performing glucose testing in patients with IDA to ascertain the reliability of HbA1c in the diagnosis of diabetes. HbA1c concentrations in diabetic patients with IDA should be interpreted with caution.

MeSH terms

  • Adolescent
  • Adult
  • Anemia, Iron-Deficiency / blood*
  • Anemia, Iron-Deficiency / diet therapy
  • Anemia, Iron-Deficiency / epidemiology
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / diet therapy
  • Diabetes Mellitus, Type 2 / epidemiology
  • Dietary Supplements
  • Erythrocyte Indices
  • Fasting / blood*
  • Female
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / metabolism*
  • Humans
  • India / epidemiology
  • Iron / administration & dosage*
  • Maternal-Child Health Centers
  • Postprandial Period
  • Prediabetic State / blood*
  • Prediabetic State / diet therapy
  • Prediabetic State / epidemiology
  • Pregnancy
  • Pregnancy Complications, Hematologic / blood*
  • Pregnancy Complications, Hematologic / diet therapy
  • Pregnancy Complications, Hematologic / epidemiology
  • Pregnancy Trimester, First
  • Pregnancy Trimester, Second
  • Pregnancy Trimester, Third


  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human
  • Iron