A class of chemicals commonly used in plastic food containers and cosmetic products may have caused about 10 percent of the United States’ premature births in 2018, according to a study by environmental health experts at New York University.
The chemicals, called phthalates, are typically added to plastics such as food packaging, shopping bags and shower curtains to make them more flexible. They are also used in scented cleaning and beauty products as they make fragrances last longer. There are dozens of different types of these chemicals, and when ingested, they can interfere with hormones that regulate the reproductive system.
The NYU study, published in Lancet Planetary Health, examined a cohort of more than 5,000 mothers in the United States and found that those with the most phthalates in urine samples collected at three points during their pregnancies were the most likely to have a preterm birth to experience — a finding the researchers said is consistent with other studies. After controlling for confounding factors such as the mothers’ age, tobacco use, race and education, they estimated that phthalate exposure contributed to more than 56,000 premature births in the US in 2018.
A birth is considered premature if it occurs before 37 weeks of pregnancy, compared to 39 to 41 weeks for “term” births, and a birth that is even a week or two early can have a major impact on a have a child’s development.
“You might think a few days in a pregnancy aren’t such a big deal, but these are crucial days of fetal development,” Leonardo Trasande, an environmental health researcher at NYU and lead author of the study, told Grist. Babies born prematurely often require expensive neonatal care and are more likely to experience health problems as they get older. Taking into account those negative health outcomes—both the immediate cost of caring for premature babies and their potentially reduced productivity later in life—Trasande’s team estimated that phthalate-related premature births could cost society as much as $8.1 billion in 2018.
Phthalate exposure is just one way the plastics industry externalizes harm. Its products are naturally made from fossil fuels, and make them free billions of tons of greenhouse gases every year – not to mention toxic air and water emissions that disproportionately affect frontline communities. The material can also leach a variety of hazardous chemicals as it is used, and when incinerated, sent to a landfill, or disposed of as litter.
Less than 10 percent of plastic is recycled worldwide, and some evidence suggests that recycling actually can Increase their toxicity.
The American Chemistry Council, which represents the nation’s plastics and petrochemical industries, objected to the NYU study. The group’s high phthalate panel – which describes itself as “dedicated to promoting the benefits” of three types of phthalates — told Grist the study inappropriately grouped phthalates that are “toxicologically different from one another” and established an associative, not causal, link between the chemicals and adverse health outcomes.
“Studies like this have been criticized for lacking scientific quality, credibility and reliability,” the group said.
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Kimberly Yolton, a developmental psychologist and epidemiologist at Cincinnati Children’s Hospital Medical Center, disagreed. It is difficult to draw a direct causal link between specific chemicals and birth outcomes, she told Grist, but the large sample size included in the NYU study outlines a “very strong association” and is consistent with previous research.
“The findings reinforce many other studies that have already come out,” she added.
Indeed, the new research is not the first to raise concerns about phthalates. In 2022, s landmark study led by the National Institute of Environmental Health Sciences suggested that phthalate exposure was associated with a 14 to 16 percent greater likelihood of a preterm birth. Other research has linked phthalates to Cancer and male reproductive problemsand found that people of color face excessive exposure to them.
Scientists aren’t sure exactly how phthalates cause premature births, but some hypothesize that the chemicals lead to inflammation that can contribute to preeclampsia, a pregnancy complication characterized by high blood pressure.
In 2008, the Federal Drug Administration several phthalates banned of children’s toys, clothing and childcare items. A handful of states went further – Mainefor example, expressly prohibits the sale of food packaging containing phthalates, and Washington’s Non-Toxic Cosmetics Act ban the chemicals from personal care and beauty products.
Still, the federal government lacks strong rules for phthalates in common items like food packaging, and the chemicals remain ubiquitous. Last month, Consumer Reports tested a wide variety of fast foods and supermarket items, and phthalates found in almost everything — iced tea, chicken nuggets, canned tuna. The organization warned that the chemicals may not only come from plastic food packaging, but also from conveyor belts, pipes and other machinery used to process food. Phthalates can also enter meat when animals eat crops grown in contaminated soil or drink contaminated water.
Other common places to find phthalates include plastic wall coverings and flooring, medical devices, furniture, electronics and coatings for medications. Previous studies have found phthalates in the bodies of more than 90 percent of all adults and children sampled. Some companies have begun to replace the most common types of phthalates with less studied substitutes, but the NYU researchers found that these alternatives also increase the risk of premature birth.
To avoid phthalate exposure, Trasande suggested buying fragrance-free products and avoiding foods that come in plastic packaging. “We need to reduce our plastic footprint,” he said, suggesting stainless steel and glass as safe alternatives.
Although phthalate-free plastics exist, there are still thousands of other potentially dangerous chemicals used in the manufacture of plastics, and Trasande said it would be better to avoid the material altogether. On a more systemic level, he urged policy makers to limit plastic production as part of the global plastics treaty currently being negotiated by the United Nations.
