Prematurity is the second leading cause of death among infants in the United States and exposure to PFAS and PBDEs (chemicals in non-stick pans, water-repellent fabric, and furniture foam) during pregnancy is associated with an increased risk of preterm birth. But while there is extensive research on some of these chemicals, the effects of other, less common versions of these chemicals are less known.
We examined the effects of a larger suite of PFAS and PBDE chemicals than are usually studied on preterm birth and found concerning results. Increased prenatal exposure to BDE-47 and BDE-99 was associated with smaller infants (measured with weight z-scores). Increasing concentrations of PFOA, one of the PFAS that was phased out of production in the 2000s, was also linked to an increase in the odds of delivering preterm. Our study contributes to the body of scientific evidence that PBDEs and PFAS at current levels in the US have a negative impact on birth weight and gestational age.
Even at low levels, PFAS and PBDEs are a problem
Since the ban and phase-out of certain PBDEs and PFAS in the US in the early 2000s, levels of some of these chemicals in humans have declined over time. Indeed, levels of PFAS and PBDEs in our participants were lower than many previous studies of pregnant women. However, we are concerned that even at low levels the PFAS and PBDE chemicals measured in our study can adversely affect infant birth weight and gestational age. Furthermore, pregnant people are not exposed to only one chemical at a time, but rather a mixture of chemicals that may affect their newborns’ health.
Recent research by former PRHE postdoctoral fellow and now Emory assistant professor Stephanie Eick and colleagues found that a mixture of PFAS and PBDEs was associated with longer telomere length in newborns. Longer telomeres in newborns predicts longer telomere length in these individuals when they become adults. Other studies indicate that longer telomere length in newborns is associated with higher cancer risk.
Harmful chemicals disproportionately affect people of color
Adding to this concern, low levels of exposure may have a bigger impact in racial and ethnic minority groups who are disproportionately at risk of preterm birth. These groups can also be disproportionately burdened by multiple chemical exposures compounded by systemic racism stressors. The result is that pregnant people from marginalized social groups are in “double jeopardy,” facing the health effects of both the chemicals and social stressors. Additional research by Eick and colleagues showed that the relationship between PFAS exposure and corticotropin-releasing hormone (CRH) was stronger among pregnant people who report prenatal stressors such as food insecurity and financial hardship. CRH may be a marker of the biological mechanism linking PFAS and other chemical and non-chemical stressors with preterm birth.
Thus, more research on the impacts of persistent and legacy chemicals as well as emerging new chemical substitutes is critical to address preterm birth and remedy health inequities. PRHE is currently participating in the Environmental Influences On Child Health Outcomes (ECHO) Program, the largest NIH-funded study to date examining the impacts of harmful chemicals and environmental pollutants on mothers and children. The ECHO study, which involves over 50,000 children in the U.S., is pooling data from 56 different cohorts of mothers and/or children. This study will enable researchers to better investigate emerging and new chemicals in a larger and more diverse study population.
- Reducing exposure to chemicals during pregnancy
- Flame retardant exposure among pregnant women in California
- Associations between polyfluoroalkyl substance and organophosphate flame retardant exposures and telomere length in a cohort of women firefighters and office workers in San Francisco
About the author
Elizabeth K. Hom Thepaksorn, PhD, MPH is a senior lecturer at the Sirindhorn College of Public Health, Thailand. As a postdoc at PRHE, she researched the effects of endocrine disrupting chemicals including PFAS and PBDEs on birth outcomes. She earned her PhD in epidemiology and MPH in environmental and occupational health sciences at the University of Washington, Seattle. Her research interests include the health effects of air pollution and climate change and utilizing research to advance environmental justice.
Co-authors on this paper are Stephanie Eick, Elizabeth Hom Thepaksorn, Monika Izano, Lara Cushing, Yunzhu Wang, Sabrina Crispo Smith, Songmei Gao, June-Soo Park, Amy Padula, Erin DeMicco, Linda Valeri, Tracey J. Woodruff, and Rachel Morello-Frosch.