Pregnant women don’t drink, yet their bodies carry a cocktail of health-harming chemicals, a new study found. Researchers at the University of California, San Francisco identified 163 chemicals—including phthalates, flame retardants and long-banned pesticides—in blood and urine samples of 268 pregnant participants of the 2003-2004 National Health and Nutritional Examination Survey. While the UCSF analysis didn’t directly link these chemicals to health issues as several prior studies have, it is the first official tally of how many toxins pregnant women encounter.

The researchers chose to examine chemicals that the Centers for Disease Control and Prevention had previously detected in human blood and urine and that had shown in animal studies to be reproductive or developmental toxicants, said Ami Zota, PhD, coauthor of the study. “Many have not been examined extensively in human studies, but they’ve shown to harm the fetus in animal studies,” she said.

Researchers found phthalates, phenols, perchlorate, polychlorinated biphenyls (PCBs), organochlorine pesticides (such as DDT), perfluorinated compounds (PFCs) and polycylic aromatic hydrocarbons in 99 percent to 100 percent of pregnant women. They identified bisphenol A (BPA) in 96 percent of participants, and the antibacterial triclosan in 87 percent.

While some of these toxins have been or are being phased out of widespread commercial and industrial use—such as DDT, which was banned in the U.S. in 1972—other chemicals are found in a wide range of consumer products, meaning pregnant women are exposed to them constantly. For instance, phthalates—endocrine-disrupting plasticizers and solvents that have been linked to behavioral and developmental problems in offspring of exposed pregnant women—are common in cosmetics, personal care products and all kinds of synthetic fragrances. BPA comes from cans, plastic bottles, thermal store receipts, food packaging and microwave popcorn bags, while toothpastes and antibacterial soaps and hand sanitizers can contain triclosan.

Constant exposure

Even though a small squirt of sanitizer or 5 seconds of contact with a BPA-laced to-go container may not be enough to permeate a pregnant woman’s skin and harm the fetus—and even though humans break down these chemicals fairly easily and excrete them within a few days—it’s the regular and repeated exposure that has health experts worried. “The fact that we so consistently measure these chemicals in humans means that we’re taking them in as fast as our bodies can get rid of them, so there is a more or less constant level of exposure,” said Sarah Janssen, MD, PhD, senior scientist with the Natural Resources Defense Council. 

As for those chemicals like DDT and PCBs that the U.S. government began outlawing decades ago, they still get into the human body via a number of ways. According to Zota, DDT and its breakdown product DDE persist in the environment, bioaccumulate and work their way up the food chain to the animals that people use for food. Therefore, a steak dinner eaten today could potentially expose a woman to a pesticide used many years ago.

Lingering chemicals

Also, unlike BPA or phthalates, many of these toxins tend to linger in the body for long periods of time, up to 20 years in some cases, Zota said. DDT can dwell in lipids, while lead—another toxin detected in this study—makes its way to the bones, she explained, so a woman could realistically still be carrying around a chemical she was exposed to as a young child. As for the brominated flame retardants, they’re still present in mattresses, couches and electronics, and they persist in dust, making breathing indoor air a potential means of exposure.

And scariest of all, chemical exposure is a classic—and potentially destructive—case of a whole being greater than the sum of its parts. One toxin can trigger another, exacerbating the cumulative effects, experts say.

Why are pregnant women especially at risk?

The chemicals identified in the UCSF study can certainly spell trouble for men, women and children alike: “Studies have shown that BPA may promote the growth of aggressive breast tumors and interfere with chemotherapy treatments,” Janssen said. “Also, recently published research found women with polycystic ovarian syndrome have higher levels of BPA, and phthalates have been linked to poor sperm quality in adult men.”

However, pregnant women and those looking to conceive should take extra heed. “We do think the ovaries and female reproductive organs are sensitive targets for BPA,” Zota said. “Harm may start [to the mom and baby] as early as in utero.” As for phthalates, which ransack male sex hormones, “when a developing fetus is exposed in utero, more reproductive problems, such as hypospadia and lower testosterone in male offspring, result,” Zota said.

Even lead, which lurks in bones, can pose more problems for pregnant and breastfeeding women, whose bodies requires more calcium. “Studies have found that lead can come out of bone and back into blood,” Zota said.

Unfortunately, the concern shouldn’t wane once the baby is born: “BPA is also used in medical devices, and other studies have found that infants in the neonatal ICU have high levels of exposure, presumably because BPA is leaching from the devices into their bodies,” Janssen said. “Many other chemicals have been found in dust, which can be ingested or inhaled, especially by infants and toddlers who spend most of their time on the floor picking up things and putting them in their mouths.” 

Reduce exposure

Unfortunately, women can do little about having been exposed to lead or pesticides as a child and they can’t completely avoid all contact with phthalates, BPA and the other barrage of chemicals still found in everyday products. “You can’t shop your way out of a lot of this stuff, no matter how hard to try,” Zota said.

However, there are many things women can do to limit exposure. First of all, “try to eat as many fresh fruits and veggies as possible, rather than getting fruits and veggies from cans [which carry BPA],” Zota said. “And avoid processed foods like fast foods. The packaging can carry a lot of chemicals, and we don’t know at what point its getting into food. Also void animal fats because a lot of chemicals accumulate in fat.”

Zota also suggested avoiding first- and second-hand smoke, being mindful of air pollution and steering clear of unnecessary fragrances, such as air fresheners and many conventional personal care products.

Janssen added these tips to limiting chemical exposure: