PBDE Fire Retardant Chemicals Linked with Premature Births

The research findings on the perils of the ubiquitous endocrine-disrupting PBDE fire retardant chemicals continue to pour in.  The latest published scientific study has again found that expectant women are more likely to give birth early if they have high blood levels of a chemical used in flame retardants compared with those who have limited exposure.


These polybrominated diphenyl ethers (PBDEs) are used in the manufacture of furniture, carpeting, and other products to reduce flammability. Previous studies have found that the substances can leach into household dust and build up in the body where they may interfere with the thyroid, an organ that secretes brain-developing hormones. Childhood exposure to PBDEs has been linked to learning disabilities, autistic symptoms, and behavioral issues, among other developmental problems.

Earlier research has pointed to PBDE exposure as a possible culprit behind preterm birth*. However, these investigations only looked at exposure to the chemicals late in pregnancy and only examined white and African-American mothers.  This study is the first to explore the link between PBDE exposure in the first trimester of pregnancy. This latest investigation also looked at a wider demographic group as well, adding Asian and Hispanic women to the analysis.

Study overview

The research team analyzed blood samples from 3,529 California women, 184 of whom delivered their infants early. They measured the samples for levels of PBDE-47, a form of the chemical that commonly builds up in the household. The investigators then divided the mothers into four groups based on their amount of exposure.

The study also accounted for other risk factors linked to preterm birth, such as the mother’s ethnicity, age, and whether she smoked during pregnancy.

Study results overview

Nearly all pregnant women enrolled in the study conducted had detectable levels of PBDEs in their blood. The findings revealed that women with concentrations above 4 nanograms per milliliter of blood were roughly twice as likely to deliver their children early via cesarean section or intentionally induced labor due to safety concerns for the mother or infant. By contrast, there was no elevated risk for preterm birth among women with PBDE levels below that threshold.

Among the study findings, the group with the highest PBDE levels had a 75 percent increased risk for a spontaneous preterm birth compared with women who had the lowest exposure. Such births occur when women suddenly go into early labor after an otherwise normal pregnancy.

The study findings also challenged previous beliefs about the role of thyroid hormones in the association between PBDEs and preterm birth. As part of the investigation, the researchers measured blood levels of thyroid stimulating hormone (TSH), a substance used to assess thyroid activity. If flame retardants indeed prevent the organ from working properly, thereby disrupting hormone function, then TSH levels should rise. However, the study revealed that TSH levels remained normal, suggesting that another mechanism must be at work. Scientists say a possible explanation is that PBDEs may interfere with hormones in the placenta instead of the thyroid.

*Preterm birth is a leading cause of newborn death and occurs annually in about 15 million pregnancies worldwide. Experts have linked the phenomenon to long-term neurological disorders including cerebral palsy, schizophrenia, and learning problems that can extend into adulthood. 

For more scientific study results linking numerous brain and body health conditions with PBDE chemicals, go to our blog, scroll down to the bottom of the page and enter “PBDE” in the search box.

Journal Reference: Morgan R. Peltier, Michael J. Fassett, Yuko Arita, Vicki Y. Chiu, Jiaxiao M. Shi, Harpreet S. Takhar, Ali Mahfuz, Gildy S. Garcia, Ramkumar Menon, Darios Getahun. Women with high plasma levels of PBDE-47 are at increased risk of preterm birth. Journal of Perinatal Medicine, 2020; 0 (0) DOI: 10.1515/jpm-2020-0349