If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Urine levels of toxic or concerning chemicals are high during pregnancy

Black and Hispanic women show higher exposures to several chemical types than White women

by Alla Katsnelson, special to C&EN
May 18, 2022 | A version of this story appeared in Volume 100, Issue 18


Pregnant women have a high level of exposure to dozens of chemicals that may harm the developing fetus, according to new research (Env. Sci. & Technol., 2022, DOI: 10.1021/acs.est.1c08942). This chemical burden is increased in Black and Hispanic women as well as in women with less educational attainment, reports the study, which was the largest one to date to track exposure to such a high number of chemicals in a diverse sample of pregnant participants.

chemical structures of bisphenol A, bisphenol S, and Clothianidin.

The study “reminds us that we have this tremendous body burden of chemicals that either have been proven toxic or haven’t been proven safe yet,” says Bruce Lanphear, an environmental health scientist at Simon Fraser University, who wasn’t involved in the work. “It raises the question again of are we doing enough to protect pregnant women and developing fetuses from all these toxic chemicals that we are all exposed to.”

The study, part of a US program called Environmental influences on Child Health Outcomes (ECHO), analyzed urine samples from 171 women, 60% of whom were Black or Hispanic, in five US states and Puerto Rico. Most samples were collected between 2017 and 2020. The researchers homed in on 103 chemicals from 9 chemical categories with known or likely human toxicity, including bisphenols, insecticides, organophosphate esters, and phthalates. Some of the chemicals were metabolic breakdown products of parent compounds from these categories. Several of the chemicals found are not yet monitored by government regulatory agencies for their effects on human health but have either shown signs of toxicity or are structurally similar to compounds that have.

The team looked for these chemicals using a new mass spectrometry–based method that “for the first time was able to measure multiple chemicals in multiple groups in a small amount of urine sample,” says Jessie P. Buckley, an environmental epidemiologist at Johns Hopkins University, who co-led the work.

At least 30 compounds were detected in more than half the women in the study. The researchers found 73 of the target analytes at least once in the urine samples. The researchers also found higher levels of chemicals from several chemical types, including parabens, phthalates, and bisphenols, neonicotinoids, phthalates, and polycyclic aromatic hydrocarbons, in Hispanic women than in White women, and higher levels of parabens in Black women than in White women. “Some beauty products or other personal care products and foods may contribute to this,” says Buckley, but further studies are needed to pin down the cause.

The researchers also found increasing exposures to newer chemicals that are replacing older ones being phased out by regulations or market forces. For example, urine levels of bisphenol A and certain phthalates and parabens stayed steady or declined over the years measured in the study. Yet levels of molecules introduced to replace them, such as bisphenol S and bisphenol F, appear to be increasing. These trends were “pretty robust for these replacement chemicals,” says Tracey J. Woodruff, an environmental health scientist at the University of California, San Francisco, who co-led the work.

One surprise was that the researchers detected high levels of exposure to neonicotinoid pesticides (such as clothianidin, shown), Woodruff says. “That wasn’t really on my radar.” These chemicals are replacing organophosphates and other pyrethroids in agriculture and are also increasingly used in homes for insect control, but there are strong hints that they can harm human health, she says.

An ongoing larger study, sampling exposures in more than 6,000 pregnant women, will make it possible for researchers to ask a wide range of questions about how specific chemical exposures relate to pregnancy outcomes, Woodruff says.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.