title: Associations between polybrominated diphenyl ether (PBDE) flame retardants, phenolic metabolites, and thyroid hormones during pregnancy.
abstract: BACKGROUND
  Polybrominated diphenyl ethers (PBDEs) are chemical additives used as flame retardants in commercial products. PBDEs are bioaccumulative and persistent and have been linked to several adverse health outcomes.
  
  
  OBJECTIVE
  This study leverages an ongoing pregnancy cohort to measure PBDEs and PBDE metabolites in serum collected from an understudied population of pregnant women late in their third trimester. A secondary objective was to determine whether the PBDEs or their metabolites were associated with maternal thyroid hormones.
  
  
  METHODS
  One hundred forty pregnant women > 34 weeks into their pregnancy were recruited into this study between 2008 and 2010. Blood samples were collected during a routine prenatal clinic visit. Serum was analyzed for a suite of PBDEs, three phenolic metabolites (i.e., containing an -OH moiety), and five thyroid hormones.
  
  
  RESULTS
  PBDEs were detected in all samples and ranged from 3.6 to 694 ng/g lipid. Two hydroxylated BDE congeners (4´-OH-BDE 49 and 6-OH-BDE 47) were detected in > 67% of the samples. BDEs 47, 99, and 100 were significantly and positively associated with free and total thyroxine (T4) levels and with total triiodothyronine levels above the normal range. Associations between T4 and PBDEs remained after controlling for smoking status, maternal age, race, gestational age, and parity.
  
  
  CONCLUSIONS
  PBDEs and OH-BDEs are prevalent in this cohort, and levels are similar to those in the general population. Given their long half-lives, PBDEs may be affecting thyroid regulation throughout pregnancy. Further research is warranted to determine mechanisms through which PBDEs affect thyroid hormone levels in developing fetuses and newborn babies.
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, North Carolina, USA. heather.stapleton@duke.edu
authors.forename: Heather M
authors.initials: HM
authors.lastname: Stapleton
authors.forename: Sarah
authors.initials: S
authors.lastname: Eagle
authors.forename: Rebecca
authors.initials: R
authors.lastname: Anthopolos
authors.forename: Amy
authors.initials: A
authors.lastname: Wolkin
authors.forename: Marie Lynn
authors.initials: ML
authors.lastname: Miranda
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005411:Flame Retardants / Q000378:metabolism*; D055768:Halogenated Diphenyl Ethers / Q000097:blood*; D006801:Humans; D010636:Phenols / Q000097:blood*; D011247:Pregnancy; D013963:Thyroid Hormones / Q000097:blood*; D055815:Young Adult
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D010636:Phenols; D013963:Thyroid Hormones