title: The relationship between maternal folate status in pregnancy, cord blood folate levels, and allergic outcomes in early childhood.
abstract: BACKGROUND
  Dietary changes may epigenetically modify fetal gene expression during critical periods of development to potentially influence disease susceptibility. This study examined whether maternal and/or fetal folate status in pregnancy is associated with infant allergic outcomes.
  
  
  METHODS
  Pregnant women (n=628) were recruited in the last trimester of pregnancy. Folate status determined by both food frequency questionnaires and folate levels in maternal and cord blood serum was examined in relation to infant allergic outcomes at 1 year of age (n=484).
  
  
  RESULTS
  Infants who developed allergic disease (namely eczema) did not show any differences in cord blood or maternal folate levels compared with children without disease. Although maternal folate intake from foods was also not different, folate derived from supplements was higher (P=0.017) in children with subsequent eczema. Furthermore, infants exposed to >500 μg folic acid/day as a supplement in utero were more likely to develop eczema than those taking <200 μg/day (OR [odds ratio] =1.85; 95% CI 1.14-3.02; P=0.013), remaining significant after adjustment for maternal allergy and other confounders. There was a nonlinear relationship between cord blood folate and sensitization, with folate levels <50 nmol/l (OR=3.02; 95% CI 1.16-7.87; P=0.024) and >75 nmol/l (OR=3.59; 95% CI 1.40-9.20; P=0.008) associated with greater sensitization risk than levels between 50 and 75 nmol/l.
  
  
  CONCLUSIONS
  Fetal levels between 50 and 75 nmol/l appeared optimal for minimizing sensitization. While folate taken as a supplement in higher doses during the third trimester was associated with eczema, there was no effect on other allergic outcomes including sensitization. Further studies are needed to determine the significance of this.
authors.affiliation: School of Paediatrics and Child Health, Centre for Child Health Research, University of Western Australia, Perth, WA 6001, Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Dunstan
authors.forename: C
authors.initials: C
authors.lastname: West
authors.forename: S
authors.initials: S
authors.lastname: McCarthy
authors.forename: J
authors.initials: J
authors.lastname: Metcalfe
authors.forename: S
authors.initials: S
authors.lastname: Meldrum
authors.forename: W H
authors.initials: WH
authors.lastname: Oddy
authors.forename: M K
authors.initials: MK
authors.lastname: Tulic
authors.forename: N
authors.initials: N
authors.lastname: D'Vaz
authors.forename: S L
authors.initials: SL
authors.lastname: Prescott
mesh_terms: D000328:Adult; D004032:Diet; D019587:Dietary Supplements / Q000009:adverse effects; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*; D007223:Infant; D007231:Infant, Newborn; D011247:Pregnancy / Q000097:blood*; D011297:Prenatal Exposure Delayed Effects / Q000097:blood*
chemical_list: D005492:Folic Acid