A highly diverse group of pregnant individuals in the United States were exposed to a number of potentially harmful chemicals from plastics, pesticides, and other sources, according to the largest study of its kind.
Some chemicals were replacements for others that are banned or are being phased out due to their potential toxicity. Many individuals in the study were exposed to neonicotinoid insecticides, which are also implicated in the decline of bee populations.
Pregnant individuals can be exposed to chemicals in food, water, air, dust, and through the use of personal care and other consumer products. Many of these chemicals can pass to the developing fetus.
“This study helps further identify which — and how much — specific chemicals humans are exposed to,” said study author John Meeker, ScD, a professor of environmental health sciences and global public health at the University of Michigan’s School of Public Health.
He said this information could focus research efforts on the chemicals that pregnant individuals are most exposed to. This includes gaining a better understanding of the negative health effects of the chemicals and how people are exposed to them.
Researchers measure women’s chemical exposures
The study included 171 pregnant women from five states — California, Georgia, Illinois, New Hampshire, New York — and Puerto Rico. About 60 percent of the group identified as Black or Hispanic about 34 percent were non-Hispanic white.
Women were participating in the National Institutes of Health Environmental influences on Child Health Outcomes (ECHO)Trusted Source program.
Urine samples collected from 2017 to 2020 were used to measure women’s exposure to 103 chemicals from pesticides and plastics, including replacement chemicals for BPA and phthalates.
Urine samples collected from 2017 to 2020 were used to measure women’s exposure to 89 analytes or chemical substances representing 103 chemicals. These included chemicals from pesticides and plastics and replacement chemicals for BPA and phthalates.
Researchers looked for certain biomarkers of those chemicals in the urine — either the chemicals themselves or products that occur when the chemicals break down in the body.
Over 80 percent of those biomarkers were detected in at least one woman in the study. In addition, 40 percent were found in over half of the women.
Barbara Cohn, PhD, MPH, researcher, and director of Public Health Institute’s Child Health and Development Studies, said this is the “most comprehensive assessment of chemical exposures in pregnant women.”
Importantly, she said researchers focused their efforts on the chemicals that are most likely to be potentially harmful.
“This is not a random list of chemicals but is instead a targeted list where concern is based on legitimate science,” she said, including work done in population science, epidemiology, experimental toxicology, environmental science, and engineering.
For example, one group of analytes that the researchers investigated were phthalates and phthalate alternatives. These chemicals make plastics more durable and can be founding vinyl flooring and personal-care products like soaps and shampoos. Phthalates have been found to affect the reproductive health of animals, and their effects, in low doses, on human health are not fully understood, according to the Centers for Disease Control and Prevention.Trusted Source
Some of the biomarkers that were found in the majority of women are not currently monitored as part of the National Health and Nutrition Examination Survey (NHANES)Trusted Source, a long-term study on the health of adults and children in the United States.
In fact, the vast majority of the thousands of chemicals used in the country are not monitored by NHANES. This includes chemicals suspected of being toxic and replacements for chemicals being phased out.
“When this [lack of monitoring] is combined with the current stance in this country — which tends to be ‘innocent until proven guilty’ when it comes to regulating chemicals — it results in the potential for overexposure to many chemicals that could be harmful,” said Meeker.
Cohn agreed, saying, “If you do not measure toxic chemicals in humans, you cannot know the extent of their presence. … Ignorance is a dangerous public policy.”