Chemical exposures during pregnancy rose over last decade

By Ariel Wittenberg | 05/10/2022 01:37 PM EDT

New research found that more than 80 percent of the chemicals analyzed were found in at least one of the women in the study.

A pregnant person.

A new study looks at chemical exposure risks during pregnancy. Andy445/iStock

A national study looking at women who were pregnant in the last 12 years found that exposure to chemicals from plastics and pesticides has increased over time, even as some compounds have been banned.

Published today in Environmental Science and Technology, the study looked at urine samples of 171 pregnant women taken through the National Institutes of Health’s Environmental Influences on Child Health Outcomes (ECHO) Program and measured 103 chemicals, mostly from pesticides and plastics.

The women in the study were from five states and Puerto Rico, and the researchers found that, across all locations and ethnicities, more recent urine samples included additional chemicals, with more than one-third of the chemicals tested found in the majority of participants.


By looking at urine samples taken in different years, the researchers were able to track the use of “replacement chemicals” — compounds used as substitutes once other chemicals were banned. The study found that, as chemicals like bisphenol A, also known as BPA, were phased out due to concerns over their health effects, new but similar compounds, like bisphenol F and bisphenol S, appeared in the urine samples.

“This data shows what happens if you don’t look at chemicals holistically as a class — you get other chemicals substituting in, which can have the same health effects or be more harmful,” said study senior author Tracey Woodruff, director of the University of California, San Francisco, Program on Reproductive Health and the Environment. “This adds more data to what scientists and public health groups have been saying, which is that we need to address chemicals by classes and not just individually.”

The study is the largest ever to measure so many chemicals in such an ethnically and geographically diverse group of women during pregnancy. Because of that, the study authors say that their findings are likely indicative of widespread chemical exposures experienced by all pregnant people nationwide.

More than 80 percent of the chemicals in the study were found in at least one of the women in the study. The study also found that many women, including those who did not live in agricultural areas, had been exposed to neonicotinoids, a pesticide that is toxic to bees.

Roughly one-third of the women in the study were white, while 40 percent were Black and 20 percent were Latina. Generally, exposures were higher for non-white women, those who had not had as much education, those who were single or those who had also been exposed to tobacco. Latinas in particular had high levels of parabens, phthalates and bisphenols in their urine. All three of those chemicals are common in certain personal care products often marketed to and used by people of color (Greenwire, June 22, 2021).

“While pesticides and replacement chemicals were prevalent in all women, we were surprised to find that Latinas had substantially higher levels of parabens, phthalates and bisphenols,” said Jessie Buckley, a professor at Johns Hopkins Bloomberg School of Public Health and first author of the study. “This could be the result of higher exposures to products with chemicals, such as processed foods or personal care products.”

All 103 chemicals included in the study are suspected to harm pregnancy and child development, but few are routinely monitored in people. It’s also not yet clear whether these chemical exposures had any impact on the women’s pregnancy or their children’s development.

Woodruff and Buckley now plan to launch an even larger study of 6,000 women included in the NIH’s ECHO Program to see if more racial or geological trends in exposure can be identified. They also are interested in following data kept by the ECHO Program on women and their pregnancies and babies to see whether they experienced any health problems that could be linked to their chemical exposures.

“Thanks to the ECHO Program, all of those participants are still being followed, so we have a lot of data to look at future outcomes,” Buckley said.