title: Iron deficiency in early pregnancy using serum ferritin and soluble transferrin receptor concentrations are associated with pregnancy and birth outcomes.
abstract: OBJECTIVE
  There are several biomarkers for measuring iron deficiency (ID) in pregnancy, but the prevalence of ID and its association with inflammation and adverse pregnancy outcomes is inconclusive. The aim of this work was to describe the prevalence and determinants of first trimester ID and associations with pregnancy and birth outcomes.
  
  
  METHODS
  A record-linkage cohort study of archived serum samples of women attending first trimester screening and birth and hospital data to ascertain maternal characteristics and pregnancy outcomes. Sera were analysed for iron stores (ferritin; μg/l), lack of iron in the tissues (soluble transferrin receptor (sTfR); nmol/l) and inflammatory (C-reactive protein (CRP); mg/dl) biomarkers. Total body iron (TBI) was calculated from serum ferritin (SF) and sTfR concentrations. Multivariate logistic regression analysed risk factors and pregnancy outcomes associated with ID using the definitions: SF<12 μg/l, TfR ⩾ 21.0 nmol/l, and TBI<0 mg/kg.
  
  
  RESULTS
  Of the 4420 women, the prevalence of ID based on ferritin, sTfR and TBI was 19.6, 15.3 and 15.7%, respectively. Risk factors of ID varied depending on which iron parameter was used and included maternal age <25 years, multiparity, socioeconomic disadvantage, high maternal body weight and inflammation. ID, defined by SF and TBI but not TfR, was associated with reduced risk of gestational diabetes mellitus (GDM). ID defined using TBI only was associated with increased risk of large-for-gestation-age (LGA) infants.
  
  
  CONCLUSIONS
  Nearly one in five Australian women begin pregnancy with ID. Further investigation of excess maternal weight and inflammation in the relationships between ID and GDM and LGA infants is needed.
authors.affiliation: Clinical and Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: A Z
authors.initials: AZ
authors.lastname: Khambalia
authors.affiliation: School of Health Sciences, Faculty of Health and Medicine, Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: C E
authors.initials: CE
authors.lastname: Collins
authors.affiliation: Clinical and Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: C L
authors.initials: CL
authors.lastname: Roberts
authors.affiliation: Clinical and Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Morris
authors.affiliation: Division of Perinatal Research, Kolling Institute, University of Sydney, Royal North Shore Hospital, St Leonards, NSW, Australia.
authors.forename: K L
authors.initials: KL
authors.lastname: Powell
authors.affiliation: Clinical and Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: V
authors.initials: V
authors.lastname: Tasevski
authors.affiliation: Clinical and Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Nassar
mesh_terms: D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D001315:Australia / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000453:epidemiology; D005260:Female; D005293:Ferritins / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D007501:Iron / Q000097:blood; D016015:Logistic Models; D015999:Multivariate Analysis; D011247:Pregnancy; D011256:Pregnancy Outcome; D015995:Prevalence; D011990:Receptors, Transferrin / Q000097:blood*; D012307:Risk Factors; D012959:Socioeconomic Factors
chemical_list: D015415:Biomarkers; D011990:Receptors, Transferrin; D002097:C-Reactive Protein; D005293:Ferritins; D007501:Iron