Fifty-five chemicals never before reported in humans were found in pregnant women, according to a study from the University of California, San Francisco. The chemicals likely come from consumer products or industrial sources, researchers say.
Findings were published online in Environmental Science and Technology.
Co-first authors Aolin Wang, PhD, and Dimitri Panagopoulos Abrahamsson, PhD, postdoctoral fellows in UCSF’s obstetrics and gynecology department, and colleagues found 109 chemicals in the blood of pregnant women, including 42 “mystery chemicals” whose sources and uses are not known.
The chemicals were also found in their newborns, tests from umbilical cord blood show, suggesting the chemicals cross through the placenta.
Among the chemicals, 40 are used as plasticizers, 28 are used in cosmetics, another 25 are used in consumer products, 29 as pharmaceuticals, 23 as pesticides, three as flame retardants, and seven are PFAS [per- and polyfluoroalkyl substances] compounds used in multiple applications including carpeting and upholstery, the authors report.
Senior author Tracey Woodruff, PhD, MPH, characterized their discoveries as “disturbing.”
She told this news organization that it’s not only frustrating to know the chemicals are present but to know so little about them.
“We know it’s a chemical registered to be manufactured, and it’s used in commerce, but we don’t know where,” she explained. “That’s very disturbing, that we can’t trace them, and that shows a failure in public policy and government.”
“Exposures are occurring without our consent,” said Ms. Woodruff, a former U.S. Environmental Protection Agency scientist, who directs the Program on Reproductive Health and the Environment (PRHE) and the Environmental Research and Translation for Health (EaRTH) Center, both at UCSF.
She said researchers know from previous studies that when the U.S. government acts to remove harmful chemicals from the marketplace, the levels of those chemicals measured in people drop.
“Examples include lead, certain PFAS, flame retardant chemicals, and certain phthalates,” she said. “So public policies can be effective in preventing exposures that can be harmful.”
Technological advances led to the discoveries
The team used high-resolution mass spectrometry (HRMS) to identify human-made chemicals in people.
Dr. Abrahamsson said in an interview that the technology is relatively new in research and had not previously been used to scan for chemicals in pregnant women and their infants.
Because scientists often study what other scientists have studied, he said, the same chemicals tend to get attention. The wider scope made possible by the new technology helps illumine where to focus future research, he said.
A benefit of the technology is that now researchers don’t have to know which chemicals they are looking for when they scan blood samples, but they can observe whatever appears, he said.
Ms. Woodruff said, “We hope this is further data and evidence that support government policies that require industries to tell us where they are using their chemicals and how we might be exposed to them.”
She said this research will also help identify which chemicals to prioritize for monitoring in the environment.
Average age of the women in the study was 32 years. Nearly half were Hispanic; 37% were non-Hispanic Whites; and 17% were non-Hispanic Asians, Pacific Islanders, and African Americans. Half of the participants were born outside the United States and had lived in the U.S. for an average 22 years.
Sean Palfrey, MD, a professor of clinical pediatrics and public health at Boston University, said more chemical discoveries like these will come as technology continues to evolve.
Dr. Palfrey, who was not involved in the study, agrees with the authors that there is a lack of oversight as to what substances are used in products.
“Our industrial regulations are very poor and therefore our industries get away with using new and untested substances in their products,” he told this news organization.
“This lack of regulation is really important when it results in us not recognizing that known and serious toxins are being put into foods or other products, or when a new class of toxin has been invented which is a serious poison. Most of the toxins, though, are discovered in products in very low levels,” he said.
Dr. Palfrey said, however, that focus should stay on the known and serious toxins that seep into the environment from common products.
“It has taken us decades to ban certain flame retardants from home products,” he said. “TOSCA [the Toxic Substances Control Act passed by Congress in 1976] was too limited when it was passed decades ago and is now fearfully out of date. Unless we discover a COVID among the toxins discovered in studies like this, we should focus on the big stuff.”
The authors and Dr. Palfrey have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.