Study on Cancer-Causing Chemicals in Pregnancy: How to Limit Exposure

Pregnant people are unknowingly being exposed to harmful chemicals that can increase the risk of cancer and harm child development, according to a new study by a team of researchers at University of California, San Francisco, and Johns Hopkins Bloomberg School of Public Health.

The team measured 45 harmful chemicals in the urine samples of 171 pregnant women across the U.S. and Puerto Rico and found detectable levels of the chemicals melamine and cyanuric acid in all but one of the study’s participants, and detected another class of chemicals known as aromatic amines in nearly all of the women.

Melamine has been classified as carcinogenic (cancer causing) by the World Health Organization, and aromatic amines are a class of chemicals that includes several types that have been found to be carcinogenic in research and real-life settings, according to the National Library of Medicine.

“This is the first study to reveal melamine and similar carcinogenic chemicals in U.S. pregnant women, none of which are being routinely monitored by the Centers for Disease Control and Prevention,” Jessie Buckley, Ph.D., co-author of the study and an associate professor at Johns Hopkins Bloomberg School of Public Health, told TODAY.

With cancer being the second most common cause of death in the U.S. — taking the lives of about 1,670 Americans every day — the study’s authors said they hope their findings can help other researchers understand how cancer-causing chemicals impact pregnant people and how exposure to such chemicals could be limited. 

In addition to increasing cancer risk, exposure to chemicals like melamine has also been linked to kidney problems in adults and children, Giehae Choi, Ph.D., study co-author and postdoctoral fellow at Johns Hopkins Bloomberg School of Public Health, told TODAY. She pointed to the 2008 incident where nearly 300,000 of children were sickened and six died after consuming infant formula contaminated with melamine. More than one in 10 of the sick children show signs of kidney damage, the Associated Press reported at the time.

“These chemicals are of serious concern due to their links to cancer and developmental toxicity,” Tracey Woodruff, Ph.D., co-author of the study and professor of reproductive medicine at UCSF, said in a press release. Developmental toxicity refers to when substances can “interfere with normal development and cause adverse effects in the offspring,” according to the National Toxicology Program.

What’s more, the study also showed that women of color had disproportionally higher levels of the harmful chemicals in their urine compared to white participants. “Most of the chemicals we detected were higher in Hispanic and non-Hispanic Black participants,” Woodruff told TODAY.

For example, levels of a chemical used in the production of dyes and pesticides were “more than 100% higher among Black and Hispanic women” compared to their white counterparts, she explained. “Since these chemicals may be harmful to maternal health and child development, they may disproportionately impact communities of color and contribute to health disparities.”

This is the latest research the team has conducted measuring the impact of various classes of harmful chemicals on pregnancy. Overall, they’ve found that there’s “widespread exposure to chemicals in multiple groups during pregnancy, which could have important implications for the health of both mothers and children,” Buckley said.

Woodruff added: “While most people aren’t familiar with these chemicals, they are found in many everyday products,” such as mascara, hair dye, plastics, vehicle exhaust, disinfectants, tobacco, dish ware and a common chlorine stabilizer for swimming pools.

How to limit exposure to toxic chemicals during pregnancy

While it’s nearly impossible to avoid exposure to such chemicals completely, the team stressed that there are some simple steps that can be taken to limit exposure. “There are several easy, low-cost ways to reduce your chemical burden,” Woodruff said. 

She recommended eating fresh and organic food when possible, not storing foods or liquids in plastic containers, and not microwaving foods in plastic dishes, as heat can make harmful chemicals more likely to seep into one’s food. UCSF’s Program on Reproductive Health and the Environment also offered the following tips:

  • Cook with cast iron or stainless steel rather than non-stick pans
  • Limit cosmetics use, especially of those with fragrances
  • Avoid dry cleaning or stain treating clothes
  • Remove shoes before entering the home
  • Avoid harsh cleaners, especially with fragrances, and opt for water and vinegar instead
  • Avoid products with flame retardants

Woodruff also said that improved regulation and education is important to help consumers make better decisions about the kinds of products they use “because chemical producers are not required to tell the government or (consumers) all the places that these chemicals are used.”

She added there’s been no requirement or burden on chemical producers to submit health data on the chemicals they use and that without such information, the public is left to piece together health effects after exposures already occur. “To address this requires systemic solutions, which include public policies to provide an equitable reduction of toxic chemicals,” Woodruff said.