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Study Finds High Levels of Toxic Chemicals in Mothers' Breast Milk

Woman breastfeeding a child.

Paulo Sousa / EyeEm / Getty Images

Key Takeaways

  • PFAS, a class of toxic chemicals, can lead to health issues in people exposed to them.
  • In a study of 50 mothers, all participants carried traces of the chemicals in their breast milk.
  • Experts say the findings indicate a need for better industry regulations.

People around the world are exposed to toxic chemicals called PFAS. Found in fast food packaging, some drinking water, and even non-stick pans, these chemicals can build up in the body over time and cause health issues. For expectant and new mothers, these foreign toxins may affect not only their health but the health of their children.

In a new study, researchers analyzed the breast milk of 50 women and discovered traces of per- and polyfluoroalkyl substances (PFAS) in every sample. The study, which was published in the journal Environmental Science and Technology last week, is the first of its kind to analyze PFAS in the breast milk of American women since 2004.

“When we see chemicals like PFAS present in breast milk, it's really a sign that we need to think more carefully about what chemicals are allowed for use in products in the U.S.,” senior study author Erika Schreder, science director at Toxic-Free Future, tells Verywell.

While experts say this information is worrisome, breastfeeding still remains hugely beneficial for health outcomes for both children and mothers.  

“This information is cause for concern," Schreder says. "But we need to remember that breastfeeding has very important health benefits and make our goal the elimination of PFAS uses so that breast milk is free from contamination."

There are a few things that pregnant or new mothers can do to lower their exposure, including drinking bottled water instead of contaminated drinking water and avoiding fast food. But while it’s important to be aware of your exposure, you shouldn't be too concerned.

“We need to be sure that people are aware of the situation, but we don't want them to be panicking,” Vasilis Vasiliou, PhD, chair of the department of environmental health sciences at Yale University, tells Verywell.

High Levels of PFAS in Breast Milk

Fifty women from the Seattle area were involved in the study. These women didn’t appear to drink water contaminated by PFAS and were mostly exposed to the chemicals through their diets and indoor exposure.

The researchers tested for 39 different PFAS, including nine compounds that are still in use in the U.S. They detected 16 total PFAS, 12 of which were detected in 50% of the samples. They found concentrations of the chemicals ranging from 52 to more than 500 parts per trillion (ppt).

There are no standards for a safe amount of PFAS in breast milk, but the Environmental Working Group says drinking water should contain no more than 1ppt. The federal Agency for Toxic Substances and Disease Registry recommends as little as 14ppt in children’s drinking water.

“We've been concerned because the chemicals were so similar that once they were well studied enough, we would start to see the toxicity and the persistence and bioaccumulation,” Schreder says. “This study provides evidence that these chemicals are persisting and building up in our bodies. At the same time, evidence of toxicity has also been growing.”

The researchers also analyzed current data on PFAS from around the world and found that these chemicals were on the rise globally, doubling in number every four years.

The 'Forever Chemical'

PFAS is a class of more than 9,000 chemicals. PFAS can be found in food packaged in materials that contain PFAS, like fast food wrappers. It may also be in:

  • Stain and water-repellent fabrics
  • Nonstick pots and pans
  • Paints
  • Cleaning products
  • Fire-fighting foams

Some industries, like electronics manufacturing or oil recovery, use PFAS. And it can contaminate drinking water or food that’s grown in contaminated soil or from animals who have consumed the chemicals. A 2016 study found that more than 6 million U.S. residents drink trap water that exceeds the EPA’s lifetime health advisory for the chemical.

Because of their composition, PFAS can remain in the environment for a long time and are thought of as "forever chemicals." Once a person is exposed, the chemicals can build up in the body, too, leading to higher concentrations over time.

Before being phased out of use in the U.S., the two most abundant PFAS were perfluorooctabesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Since the production of these two chemicals was outlawed, their prevalence in the environment is slowly declining. However, the researchers in this latest study found traces of several phased-out PFAS in breastmilk, indicating people are still being exposed to the chemicals and passing them to children.

When PFOS and PFAS were phased out, industry leaders assured the public that the other chemicals would not have the same level of toxicity or accumulate as well. Researchers say their work shows that the PFAS currently being produced similarly harm the body, and their use should be reassessed.

“This is the new era of environmental sciences,” Vasiliou says. “PFAS is going to change our lives, whether we want it or not.”

What This Means For You

If you are a mother of an infant or an expecting mother, experts say not to panic about your potential exposure to PFAS or the ability to pass it to your child. Breastfeeding can lead to many positive health outcomes for both babies and mothers. If you’re concerned about PFAS, you can learn about some ways you can limit your exposure here.

How PFAS Affect Health 

PFAS are linked to health problems including:

  • Weakening of the immune system
  • Cancer
  • Increased cholesterol
  • Liver damage
  • Thyroid disease
  • Decreased fertility

Studies have found that the build-up of PFAS in the body is linked to higher cholesterol levels. There is also evidence that PFAS can cause damage to the central nervous system, can cause pregnancy-induced hypertension, and hamper the immune system. 

While there are not yet many studies on how PFAS affects fetuses in development, Vasiliou says any level of toxicity could be dangerous.

“Development is a very delicate process—anything that you add, especially foreign and persistent, could alter this process and cause some problems,” Vasiliou says. 

“I believe that these molecules are evil,” Vasiliou says. “The basic toxicology is: the less a foreign chemical stays in your body, the better. With the longer it stays, it's going to cause some issues.” 

Currently, there is no way to remove PFAS from the body once they’ve accumulated there, though Vasiliou says researchers are studying ways to achieve this.

Creating a Contaminant-Free Future

To fully prevent PFAS from contaminating breastmilk, mothers must be able to avoid even low levels of exposure to the chemicals. People may choose not to purchase carpets treated with steam protectants or baking pans coated in Teflon. For the roughly 15% of Americans who rely on water from private wells rather than public systems, it’s good practice to test your water for toxins.

However, with the many sources of PFAS exposure in most people’s daily lives, it can be nearly impossible to completely avoid them.  Schreder says the responsibility to regulate these toxins should fall on lawmakers, environmental oversight agencies, and corporations.

Some food companies—including McDonald’s, Panera, and Taco Bell—moved away from PFAS in their food packaging. Home Depot and Lowe’s committed to not selling carpets treated with the chemicals. And some state and local governments have implemented regulations on PFAS.

As policymakers work toward regulating industries that use PFAS, Schreder says it’s important to outlaw the entire class of chemicals, rather than just a few.

“If we want to make pregnancy and breastfeeding safe and free from PFAS, we really need to eliminate the use of these chemicals and products, so that we can have clean food, clean air, and clean water,” Schreder says. “We really don't believe that responsibility should be placed on individuals when we need regulations to end the use of these chemicals.”

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  1. Zheng G, Schreder E, Dempsey J et al. Per- and Polyfluoroalkyl Substances (PFAS) in Breast Milk: Concerning Trends for Current-Use PFAS. Environ Sci Technol. 2021. doi:10.1021/acs.est.0c06978

  2. Hu X, Andrews D, Lindstrom A et al. Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. Environ Sci Technol Lett. 2016;3(10):344-350. doi:10.1021/acs.estlett.6b00260

  3. United States Environmental Protection Agency. Basic Information on PFAS. Updated April 6, 2021. 

  4. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Perfluoroalkyls. Updated March 2020.