June 18, 2026
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Many chemicals women are inadvertently exposed to during pregnancy are associated with increased risk of pre-term birth and lower birth rate, a new study finds.
Pregnant women are exposed to as many as 45 chemicals found in everything from food and water to personal care products and household items, a large new study says.
This exposure is linked to increased risk of pre-term birth and low birth weight – factors that have an ongoing impact on children's development, according to the research published Wednesday in JAMA Network Open.
"These chemicals are difficult to avoid because they're found in a wide range of products we use every day," Jessie Buckley, the study's first author and a professor of epidemiology at the University of North Carolina said in a news release. "It can be difficult to know whether products contain them, and even when we do know, we have limited control over exposures."
The research, involving more than 5,000 pairs of mothers and babies born between 2000 and 2021 in the United States, is the largest and most comprehensive study to examine exposure to several major classes of chemicals and birth outcomes, the researchers said.
They used urine samples from the pregnant women to test for more than 100 chemicals and their metabolites – chemicals that have been broken down in the body. The study also tracked whether the babies's birth weights and whether they were born early.
Even though the Consumer Product Safety Commission in 2017 banned certain phthalates and plasticizers used in many baby products, such as toys, lotions and shampoos, the new study found evidence of other phthalates and plasticizer chemicals in the pregnant women's urine samples. The chemicals included ones used as alternatives to banned and restricted chemicals.
Several of these alternative phthalates and plasticizers were associated with early delivery and low birth weight. Environmental pollutants called polycyclic aromatic hydrocarbons, or PAHs, found in the urine samples also were linked to lower birth weights.
"Our study, along with other similar findings, underscores the importance of reducing chemical exposures that impact pregnancy, as even small changes in birthweight or gestational age can have significant impacts on children's health," Buckley said in a news release.
Because the study found that several "newer chemicals used to replace toxic ones are also harmful … new and replacement chemicals must be properly evaluated before they are put on the market," said senior researcher Tracey Woodruff, a professor of epidemiology and population health at Stanford University.
