title: Predictors of haemoconcentration at delivery: association with low birth weight.
abstract: OBJECTIVE
  [corrected] To assess the factors associated with risk of haemoconcentration at delivery, such as initial haemoglobin levels and alterations in the HFE gene, and its effect on low birth weight in pregnant women supplemented with moderate doses of iron.
  
  
  METHODS
  Case-control study nested in a longitudinal study conducted on 217 healthy pregnant women taking moderate iron supplementation and their newborns. Women were classified according to the risk of haemoconcentration at delivery, defined as Hb > 130 g/L. Each subject's obstetric and clinical history, smoking habit, and iron biochemical parameters (haemoglobin (Hb), serum ferritin and transferrin saturation) were recorded at 1st, 2nd and 3rd trimester and at delivery. Polymorphisms of the HFE gene (C282Y, H63D and S65C) were also measured.
  
  
  RESULTS
  The average of iron supplementation of all the women was 43.9 mg/dia (geometric mean, 95 % CI: 43.6-44.1). Higher levels of Hb at early gestation and the presence of HFE mutations were associated with greater risk of haemoconcentration at delivery, adjusted odds ratios of 1.14 (95 % CI: 1.05-1.25) and 5.35 (95 % CI: 1.6-17.8). Haemoconcentration at delivery was associated with a greater risk of low birth weight, adjusted odd ratio of 11.48 (95 % CI: 1.13-116.6).
  
  
  CONCLUSIONS
  Moderate daily doses of supplementary iron may be harmful for foetal growth in women with alterations in HFE gene and who started pregnancy with good haemoglobin levels. Overall, this suggests the importance of determining a woman's iron status early in her pregnancy in order to establish a more appropriate pattern of supplementation.
authors.affiliation: Institut d'Investigació Sanitària Pere Virgili (IISPV), Unitat de Salut Pública i Nutrició, Universitat Rovira i Virgili, C/ Sant Llorenç 21, 43201 Reus, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Aranda
authors.forename: B
authors.initials: B
authors.lastname: Ribot
authors.forename: F
authors.initials: F
authors.lastname: Viteri
authors.forename: P
authors.initials: P
authors.lastname: Cavallé
authors.forename: V
authors.initials: V
authors.lastname: Arija
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D005293:Ferritins / Q000097:blood; D000071020:Hemochromatosis Protein; D006454:Hemoglobins / Q000737:chemistry*; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D019266:Iron, Dietary / Q000008:administration & dosage* / Q000097:blood; D008137:Longitudinal Studies; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016017:Odds Ratio; D010349:Patient Compliance; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011264:Pregnancy Trimesters; D012307:Risk Factors; D012959:Socioeconomic Factors; D014168:Transferrin / Q000737:chemistry
chemical_list: C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D006454:Hemoglobins; D015395:Histocompatibility Antigens Class I; D019266:Iron, Dietary; D008565:Membrane Proteins; D014168:Transferrin; D005293:Ferritins