Fetal Iron Status in Maternal Diabetes Versus Non-Diabetic Pregnancies
Objective: To compare the fetal iron metabolism in maternal type 1 and gestational diabetes mellitus (GDM) with non-diabetic pregnancies.
Methods: Iron, ferritin, total iron binding capacity (TIBC), soluble transferrin receptor (STfR) and hemoglobin concentration were measured in both maternal and cord blood of 91 pregnant women and soluble transferrin receptor (TfR-F) Index was calculated. Cord pH and erythropoietin were also measured. Thirty-three women had GDM and 29 had type 1 diabetes and these were compared with 29 non-diabetic pregnancies as controls. Diabetic subjects and control group who fulfilled the inclusion criteria were recruited consecutively according to the admission time to the hospital.
Results: The median duration of type 1 diabetes was 5(2-18) years and for GDM was 6(3-9) months. The controls were younger and had lower body mass index (BMI) compared with the study groups. The maternal hemoglobin concentration during pregnancy and immediately after delivery was not statistically different among diabetics and control groups.
The infants of diabetic mothers had higher birth weight than control group, but it was statistically significant only in the GDM group (P= 0.025). There wasn't any statistically significant difference in measured parameters between infants of GDM and control group, although the GDM group seemed to have lower serum ferritin level. Infants of type1 diabetes had significantly higher concentration of hemoglobin (15.9 vs 14.6 g/dl, p=0.017), lower ferritin (28.1 vs 64ng/ml, p=0.002) and considerable higher TfR-F index (0.59 vs 0.48, p=0.05) than control group. The incidence of hypoglycemia was also more in the type 1 diabetic group (p=0.004). There were 3 women in GDM and 6 women in type 1 diabetes group with poor glycemic control. Their infants had higher Hb, erythropoietin, TfR-F index and lower ferritin and iron in cord blood.
Conclusion: This study confirms that iron stores (Fe and ferritin) are lower at birth in infants of women with type 1 diabetes and the influence of type 1 diabetes on fetal iron status is more prominent than gestational diabetes.