Mounting evidence shows toxins like pesticides and other industrial chemicals may have multi-generational effects when pregnant women are exposed.

By Tina Donvito
Juan Aunion/Shutterstock

As if you weren't already worried enough about pesticides and paint fumes, now pregnant women may have another reason to be concerned about toxic chemicals. A new report by the nonprofit Environment Working Group (EWG) reveals how they may damage unborn babies' DNA and possibly affect future generations.

Babies' genes may be altered.

Called "transgenerational toxicity," these harmful effects occur when environmental toxins alter gene function in babies developing in the womb. "It suggests that some pollutants can cause damages that are passed down from generation to generation," EWG senior research analyst Sonya Lunder, the author of the report, told These gene alterations may not only affect the child a woman is currently carrying, but then may be inherited by her grandchildren and even great-grandchildren—even if they haven't been exposed to any chemicals themselves.

Unfortunately, scientists have only been able to study these effects in rats. "So far almost all of the evidence is in controlled animal studies," Lunder says. "Studying people is too complicated and it takes too long." But the rodent studies showed concerning results that may be relevant to humans, too. "Laboratory studies find a diverse group of effects to the reproductive system, and also body weight and organ development," Lunder says. "We are especially concerned about reproductive effects because they are passed down by modifying gene expression in the sperm and egg DNA."

According to the report, one study looked at the effects of chemicals we're commonly exposed to, such as those in bug repellents, plastics additives, and jet fuel. The researchers exposed pregnant rats, then bred several more generations that were not exposed. The third-generation female rats had an earlier start of puberty and fewer eggs in their ovaries, and males had higher levels of dead sperm. Another study found an increased risk of obesity in rats whose great-grandparents were exposed to the now-banned pesticide DDT.

What can pregnant women do now?

Scientists believe these multi-generational effects may be behind growing problems like infertility, developmental problems in children, and even pediatric cancers. Another issue, the report notes, is that many chemicals haven't been tested together—so even if people are exposed to each one individually at "safe" levels, the combination could be toxic.

New ways of researching chemicals together, instead of one at a time, prompted the EWG to issue the report. "The National Toxicology Program [of the US Department of Health and Human Services] has invested heavily in new research on transgenerational toxicity and reviewing existing evidence," Lunder says. "We want to draw attention and support for these government efforts." Hopefully more awareness and interest will lead to more answers.

But given how much more there still is to learn, what can pregnant women do now to reduce their chance of their child being affected and passing on altered genes? "This is a challenging question—we caution people that we need a lot more research into transgenerational toxicity before we can fully protect the developing fetus and future generations from harm," Lunder says. "In the meantime, avoiding known toxins like pesticides, paints, and industrial chemicals during pregnancy and eating healthy are the best safeguards to your health."



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