Like many parents, I scan packaging for BPA-free labels and run my sunscreen picks by the Environmental Working Group. But a November 2012 study on environmental toxins has me thinking about how little control we really have over such things. The research, published in Environmental Health Perspectives, found that higher levels of certain man-made chemicals could reduce a couple’s fertility by up to 29 percent. Many of the culpable chemicals, though, are not the ones we can pinpoint in the supermarket aisle. They circulate through our bodies even though they were banned long ago.
The Longitudinal Investigation of Fertility and the Environment (LIFE) Study— the most comprehensive to date — tracked 501 couples who had stopped using birth control with the intention of getting pregnant. The men and women kept diaries of their lifestyle habits (such as smoking), and their baby-making attempts until they got pregnant or until one year had lapsed. Researchers measured and analyzed both partners’ exposure to an array of chemicals through urine and blood samples.
Sure enough, certain chemicals were associated with taking a longer time to get pregnant. In women, the well-known and long-banned polychlorinated biphenyls (PCBs) were linked to delayed pregnancy. PCBs are man-made organic chemicals that have a reputation for toxicity and were forbidden in 1979. For decades before that year (starting in 1929) though, they were used in plastics, paints, rubber products, pigments, paper, electrical equipment, and more. Even though PCBs aren’t used now, they linger in old materials. Because they don’t break down easily, they cycle between air, water, and soil; travel far distances; and accumulate in animals like fish. Women with higher levels of another class of chemicals — perfluorochemicals (PFCs), which have been used for fire resistance, non-stick surfaces, electronics and textiles — also had longer wait times for getting pregnant. Some PFCs are being phased out, but they too have staying power in the environment.
In the LIFE study, would-be dads seem to play an even bigger role than moms: their chemical exposure showed a stronger relationship to delayed pregnancy than women’s. We know from recent research that men’s health strongly influences fertility and child development— it’s an emerging theme that is changing the way we see dad’s role in shaping his future offspring.
Men’s fertility had a similar relationship to PCBs, as well as the chemical DDE (a substance that’s produced when the pesticide DDT degrades). DDT hasn’t been used since 1973, and animal research has showed a connection with neurological problems, cancer, and reproductive effects. Both DDT and DDE remain in the environment and DDT is still used in other parts of the world.
In other words, some of the most toxic chemicals we’re exposed to aren’t exactly avoidable. The Environmental Protection Agency calls them “persistent, bioaccumulative, and toxic” and has programs in place to eliminate them from the environment slowly over time. Here’s a quick breakdown of ways we can be exposed to PCBs:
- Contaminated fish and shellfish (farmed salmon has been found to have roughly 10 times more contaminants than wild salmon or other types of fish, for example)
- Infants through breast milk (due to mom’s exposure)
- All people through regular milk, meat, and by-products thereof
- Breathing in buildings with old electrical equipment.
We’re exposed to DDT through:
- Breast milk
- Imported foods
- Foods grown in contaminated soil.
Researchers don’t know exactly why these chemicals affect fertility, but they’re thought to be “endocrine-disrupting chemicals” that alter reproductive hormones. To limit our run-ins with endocrine disruptors, the National Resources Defense Council suggests things like buying organic food when possible, avoiding pesticides, limiting farmed fish, and not heating or storing food in plastic containers.
While the EPA works on chipping away at stubborn toxins, I’ll carry this information with me (eying farmed salmon suspiciously and splurging on the wild variety, since I’m breastfeeding and have little ones in the house), but try not to get overwhelmed. Talk of chemicals and dramatic headlines can make you crazy, but it’s important to remember that even though research shows associations, it can’t pinpoint how an individual couple would be affected, if at all. How the environment affects our families is highly complex and individual — read your labels when you can and try to let the rest go.