title: Transfer of perfluoroalkyl substances from mother to fetus in a Spanish birth cohort.
abstract: BACKGROUND
  Prenatal exposure to perfluoroalkyl substances (PFAS) might affect child health; thus estimating PFAS fetal burden is relevant. PFAS fetal burden is best estimated in cord samples; previous studies have used either maternal plasma or serum during pregnancy as proxy, but their validity is not clear. We aimed to evaluate PFAS transfer between mother and fetus and determine its predictors in a Spanish birth cohort.
  
  
  METHODS
  We measured perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) in maternal blood and cord serum from 66 mother-child pairs. We used Spearman's rank coefficients to correlate PFAS concentrations in first trimester maternal plasma and serum, with cord serum samples. We assessed PFAS placental transfer by calculating maternal to cord ratios and examined their association with maternal socio-demographic characteristics and child sex using linear regression models.
  
  
  RESULTS
  Median concentrations of PFAS (ng/mL) of PFHxS, PFOS, PFOA, and PFNA in maternal plasma (0.79, 6.18, 2.85 and 0.84, respectively) and serum (0.84, 6.99, 2.97 and 0.85) were higher than in cord serum (0.40, 1.86, 1.90 and 0.32). PFBS was not detected. Positive Spearman's correlations (p-values<0.001) were found between maternal plasma and serum (⍴≥0.80), maternal plasma and cord (⍴≥0.66), and maternal serum and cord samples (⍴≥0.67). Maternal plasma to cord ratios were above 1 (PFHxS: 2.35 [95%CI: 2.05, 2.70], PFOS: 3.33 [3.05, 3.62], PFOA: 1.37 [1.27, 1.48], PFNA: 2.39 [2.18, 2.63]); maternal serum to cord ratios were similar. Maternal to cord ratios decreased with maternal age, but not with other socio-demographic factors.
  
  
  CONCLUSIONS
  Our results suggest that PFAS fetal body burden can be assessed using as proxy maternal plasma or serum collected early in pregnancy. Maternal age might influence PFAS placental transfer.
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader, 88, 08003 Barcelona, Catalonia, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Spain. Electronic address: cmanzano@creal.cat.
authors.forename: Cyntia B
authors.initials: CB
authors.lastname: Manzano-Salgado
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader, 88, 08003 Barcelona, Catalonia, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Spain.
authors.forename: Maribel
authors.initials: M
authors.lastname: Casas
authors.affiliation: CIBER Epidemiología y Salud Pública (CIBERESP), Spain; FISABIO- Universitat Jaume - Universitat de València Joint Research Unit of Epidemiology and Environmental Health, Valencia, Spain.
authors.forename: Maria-Jose
authors.initials: MJ
authors.lastname: Lopez-Espinosa
authors.affiliation: CIBER Epidemiología y Salud Pública (CIBERESP), Spain; FISABIO- Universitat Jaume - Universitat de València Joint Research Unit of Epidemiology and Environmental Health, Valencia, Spain.
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.affiliation: CIBER Epidemiología y Salud Pública (CIBERESP), Spain; Public Health Department of Gipuzkoa, San Sebastian, Spain; Health Research Institute Biodonostia, San Sebastian, Gipuzkoa, Spain.
authors.forename: Mikel
authors.initials: M
authors.lastname: Basterrechea
authors.affiliation: Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Barcelona, Spain; Spanish Council for Scientific Research (CSIC), Barcelona, Spain.
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.affiliation: Public Health Department of Gipuzkoa, San Sebastian, Spain; Health Research Institute Biodonostia, San Sebastian, Gipuzkoa, Spain.
authors.forename: Ana-María
authors.initials: AM
authors.lastname: Jiménez
authors.affiliation: Institute for Occupational Medicine, RWTH Aachen University, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kraus
authors.affiliation: Institute for Occupational Medicine, RWTH Aachen University, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schettgen
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader, 88, 08003 Barcelona, Catalonia, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader, 88, 08003 Barcelona, Catalonia, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Spain.
authors.forename: Martine
authors.initials: M
authors.lastname: Vrijheid
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004785:Environmental Pollutants / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005466:Fluorocarbons / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D016014:Linear Models; D008297:Male; D018811:Maternal Exposure; D008431:Maternal-Fetal Exchange; D021041:Placental Circulation; D011247:Pregnancy; D012959:Socioeconomic Factors; D013030:Spain
chemical_list: D004785:Environmental Pollutants; D005466:Fluorocarbons
keywords: Cord blood; INMA; Mother–child pairs; Perfluoroalkyl substances (PFAS); Pregnancy