Background: Regulation of iron transfer from mother to fetus via the placenta is not fully understood and the relationship between stored iron status in the mothers' serum and gestational diabetes (GDM) in case-control studies is controversial. The present study aimed to detect circulating soluble transferrin receptor (sTfR) and ferritin levels in maternal and umbilical cord blood. We also examined the expression of hepcidin (Hep), transferrin receptor (TfR1), and ferroportin (FPN) in the placenta in pregnant women with and without GDM at full term.
Methods: Eighty-two women participated (42 with GDM and 40 without GDM [controls]). Maternal samples were collected at 37-39 weeks' gestation. Umbilical cord blood was collected at birth. Ferritin and sTfR levels in maternal serum and umbilical cord blood, and Hep, TfR1, and FPN protein expression in plac enta were compared between the GDM and non-GDM groups. Serum ferritin (SF) was measured by electrochemiluminescence assay and sTfR was measured by ELISA. Hep, TfR1, and FPN expression was measured by immunohistochemistry.
Results: Maternal serum sTfR levels were significantly elevated in the GDM group compared with the non-GDM group (p = 0.003). SF levels in cord blood in the GDM group were significantly higher than those in the non-GDM group (p = 0.003). However, maternal hemoglobin and SF, and umbilical cord sTfR levels were not different between the groups. In placental tissue, FPN expression was higher and hepcidin expression was lower in the GDM group compared with the non-GDM group (p = 0.000 and p = 0.044, respectively). There was no significant difference in TfR1 between the groups (p = 0.898).
Conclusions: Women with GDM transport iron more actively than those without GDM at term pregnancy. Maternal iron metabolism in GDM may play a role in fetal/placental iron demand and in the overall outcome of pregnancy.
Keywords: ferritin; ferroportin; gestational diabetes; placenta; transferrin receptor 1.