Potentially harmful but commonly used chemicals were widely detected in urine samples of pregnant people, according to a new study. At least 45 individual of these chemicals were found in half of the study’s participants.
The authors measured the presence of over 100 different chemicals, choosing those that people are commonly exposed to and that have a high probability of leading to poor birth and child health outcomes.
This group of chemicals include those often found in personal care products, food, drinking water and household items, including phthalates, pesticides and polycyclic aromatic hydrocarbons, or PAHs.
The lead researchers are affiliated with the Gillings School of Global Public Health at the University of North Carolina, Stanford University School of Medicine and the Woods Institute for the Environment.
For the study, published in JAMA Network Open, scientists collected urine samples from over 5,300 pregnant women across the U.S. Of the 113 specific chemicals tested for, all but three were detected in at least one sample.
Samples were collected on average in the second trimester at multiple research sites in 14 states between 2000 and 2021.
Links to worse birth outcomes
Exposure to many of these chemicals, but especially phthalates and PAHs, were associated with shorter gestation and lower birth weights. The findings are concerning because these factors are linked to poorer long-term health and development in children.
Phthalates help make plastic flexible and stabilize fragrances in products. Commonly used phthalates and their replacements were associated with earlier delivery and increased risk of preterm birth.
PAHs make up a large class of chemicals that are produced when coal, oil, gas, wood or tobacco are burned. Car exhaust, grilling and cigarette smoke are all potential sources of exposure.
The study reported that higher levels of PAHs were associated with increased risk of lower birth weight adjusted for gestational age. This means that even when accounting for how early or late a baby was born, mothers who were exposed to higher levels of PAHs during pregnancy had babies that weighed less than expected at birth.
UNC professor of epidemiology Jessie Buckley, Ph.D. led the research. She says: “Our study underscores the importance of reducing harmful chemical exposures during pregnancy. Even small differences in birth weight or gestational age can have significant impacts on children’s health.”
‘Regrettable substitutions’ linked to same effects
The urine samples in this study were collected from participants over two decades. During that time, several chemicals found more widespread use while others were phased out, including some “high concern” phthalates banned by states or regulatory agencies for use in children’s products or food packaging.
But in these circumstances, manufacturers often replaced the concerning chemicals with structurally similar alternatives, effectively perpetuating exposures that pose similar health harms.
For example, as concern rose about exposure to one phthalate, di-2-ethylhexylphthalate, or DEHP, manufacturers replaced it with diisononyl phthalate, or DiNP.
Researchers found the replacements for common phthalates were detected in the urine samples and were associated with the same health risks as the banned substances they replaced.
One of the stronger links to shorter gestation, or earlier delivery, was driven by this replacement ingredient. For example, DiNP was significantly associated with a 16% increase in risk of preterm birth.
Today, DiNP has been phased out again in favor of other structurally similar, but different, phthalate replacements that are likely to have the same impacts on health. DiNP may still be present in products, even though the levels are heavily restricted by the Consumer Product Safety Commission.
Reducing your exposure to chemicals
The study findings highlight that exposure to harmful chemicals during pregnancy can affect birth outcomes, which may in turn influence children’s health long term. Some of the chemicals linked to birth and children’s health outcomes include phthalates found in personal care products or food packaging.
Consumers seeking safer products can read labels and consult ingredient-checking tools such as EWG’s Skin Deep® database or use EWG’s Healthy Living™ app, which includes Skin Deep.
Phthalates used in personal care products might not always show up on the label if they are part of a fragrance blend. Avoid products that do not disclose their fragrance. The umbrella term “fragrance” or “parfum” can be a blend of up to 100 ingredients, some of which may be chemicals associated with health harms.
Consumers can also choose cleaning and personal care products bearing the EWG Verified® mark, which are free from EWG’s chemicals of concern and meet strict standards for health.
Consumers who want to reduce exposure to pesticides from food residues can consult EWG’s Shopper’s Guide to Pesticides in Produce™ and download EWG’s guide to washing produce.
Efforts to reduce exposure do not require replacing everything at once. Even a small change, such as swapping out one product for a safer alternative, can be a simple way to start reducing exposure to harmful chemicals.
