[The effect of tobacco smoking during pregnancy on concentration of pro-hepcidin and some parameters of iron metabolism in matched-maternal cord pairs].

Iron deficiency relatively observed in pregnant women is assumed to be enhanced by cigarette smoking. Hepcidin, a peptide hormone produced by the liver as pro-hepcidin, has recently emerged as a central mediator of iron metabolism. Hepcidin regulates intestinal iron absorption, macrophage iron release, and the placental passage of iron. Maternal smoking is associated with increased fetal iron requirements and stimulates fetal erythropoiesis. This is probably through a hypoxic effect on the fetus, and is dose related to the maternal smoking level. It is known that anemia and hypoxia suppress hepcidine mRNA expression. Therefore the aim of the study was to estimate the effect of tobacco smoking on serum pro-hepcidin levels and some iron parameters in pregnant women and umbilical cord blood. We also studied correlation between pro-hepcidin and others iron markers in mothers and their newborns. Healthy, pregnant women (n = 50), patients of Clinical Department of Obstetrics and Gynecology, Institute of Mother and Child were divided into groups nonsmoking and smoking according to questionnaire declaration. Serum concentrations of pro-hepcidin were determined by immunoenzymathic method using a commercial pro-hepcidin assay (DRG, Germany). Levels of ferritin and transferrin were measured by immunoturbidimetric method and iron by photometric test with ferrozine using HORIBA ABX kits (France) and Cobas Mira analyser (Roche, Switzerland). Levels of hemoglobin and hematocrite were determined using commercially available kits on Pentra 60 analyser (ABX, France). We observed that the mean concentration of pro-hepcidin in serum of smoking pregnant women was statistically lower than in tobacco abstinent (101.9 +/- 28.6 ng/ml vs 88.3 +/- 18.2 ng/ml; p < 0.01). Levels of others studied iron markers were similar in both group except total iron concentration, which was 20% lower in smoking mothers than in nonsmoking ones. In umbilical cord blood of infants born to smoking women level of pro-hepcidin was significantly lower than in tobacco abstinent (54.2 +/- 14.0 ng/ml vs 76.8 +/- 21.4 ng/ml, p < 0.0001). We observed positive correlation between concentrations of that prohormone in serum of mothers and cord blood of their newborns in nonsmoking group (r = 0.54; p < 0.02) as well as in smoking ones (r = 0.68; p < 0.05). In addition, concentrations of ferritin, transferin and total iron were lower by 30%, 13% and 20% respectively in cord blood of smoking than nonsmoking group. The differences were statistically significant (p < 0.05). Our analysis revealed no correlation between serum pro-hepcidin levels and other studied parameters of iron status both in the mothers and children groups. Our results indicate that tobacco smoking during pregnancy affected pro-hepcidine levels in serum of mothers and their newborns. Low concentrations of some iron markers in umbilical cord blood suggest that mother's smoking could lead to subclinical iron deficiency in fetus. No anemia were observed in both studied groups of mothers that could explain no relationships between pro-hepcidin and others parameters of iron status.