Mazdai, A, NG Dodder, MP Abernathy, RA Hites and RM Bigsby. 2003. Polybrominated Diphenyl Ethers in Maternal and Fetal Blood Samples. Environmental Health Perspectives doi:10.1289/ehp.6146.

Press coverage

Polybrominated diphenyl ethers, or PBDEs, are widely used as flame retardants in many consumer products. Laboratory data indicate they intefere with thyroid hormone, and are thus suspected of disrupting neurological development. Experiments with neonatal mice confirm their developmental neurotoxicity. In this publication, Mazdai et al. report finding levels of brominated flame retardants in maternal and fetal serum in Indiana far exceeding levels that moved Sweden to ban PBDEs in that country.

What did they do? Mazdai et al. extracted maternal and cord blood serum from 15 women in labor from two hospitals in Indiana, and then analyzed these samples for PBDE levels. Three of the mother-infant samples were eliminated because because of quality-control issues, leaving twelve paired samples for analysis. The samples were processed through a linked gas chromatograph-mass spectrometer to determine PBDE concentrations. They also determined thyroxine (T4) and triiodothyronine (T3) levels in the serum.

None of the women worked in occupations that would lead to high PBDE exposures, nor did any smoke. No birth defects were detected in any of the infants.

What did they find? Mazdai et al. found relatively high levels of PBDEs in all samples examined. Concentrations ranged from 15 –
580 ng/g lipid in maternal serum and 14-460 ng/g in fetal samples, and the concentrations found in fetal samples ranged from 14 – 460 ng/g lipid.

Maternal and fetal PBDE levels were highly correlated (r²=0.986).

Of the six different PBDE congeners measured, BDE-47 was the most abundant, found in all samples and accounting for up to 64% of all PBDEs measured.

They found no correlation between PBDE levels and any clinical measurements taken, e.g., body weight or thyroid hormone levels.

What does it mean? In this first report of maternal and fetal PBDE levels from the United States, PBDEs were found in all samples taken. Compared to a similar sample from Sweden, these levels are 20 to 69-fold higher for US mothers and 30 to 106-fold higher for US newborns. Indeed the US levels are comparable to measurements in Sweden obtained from workers exposed occupationally. The Swedish measurements have already prompted the Swedish government to institute a ban on PBDE use in that country.

Measurements from the US 15 years ago were dramatically lower, by as much as a factor of 100.

This study indicates that body burden of PBDEs have risen greatly within the US over the past decade. While the sample size of this study is small and geographically limited, simultaneous publication of another study with similar results from California would suggest it is likely to be a widespread trend.

The near-perfect correlation between maternal and fetal samples shows that PBDEs readily cross placental barriers.

Given the powerful ability of some PBDEs to interfere with thyroid function, and the crucial role of thyroid in regulating fetal development, especially of the brain, this finding justifies urgent steps to (1) confirm the trend and (2) eliminate PBDE releases into the environment.