Doctors struggle to explain the impact of environmental toxins to pregnant patients since they have limited time and spotty information on the effects of many common chemicals.

OB-GYNs counsel their patients on just about every pregnancy-related issue, but one very important topic has gone by the wayside, according to a new study of prenatal counseling published in the journal PLOS ONE.

Exposure to environmental toxins, researchers at the University of California, San Francisco (UCSF), have found, is rarely discussed with pregnant patients, even though a national survey showed that 80 percent of physicians agree they should play a part in reducing patients’ exposure to toxins. But of the 2,500 respondents, only one in five routinely asked their patients about these exposures, and just one in 15 said they received training on the harmful reproductive effects of toxic chemicals.

Even if doctors were more knowledgeable about environmental toxins, it would be impossible to catalogue the effects of each one because many have yet to be tested. Doctors and patients generally have a limited amount of time to talk, and more immediate concerns like vitamin intake and sexual health are often at the top of patients’ priority lists.

Also, doctors reported in focus groups that they felt pregnant women were already stressed about reproductive and developmental health issues, and the doctors didn’t want to burden them further with a frightening conversation about toxins.

Recent research has shown that environmental toxins can have profound effects on fetal development. A study published last week in Environmental Health Perspectives shows that pesticide exposure can increase a woman’s risk of giving birth to a child with autism. Another study published in the same journal found that maternal exposure to air pollution is associated with low birth weight in infants. Other areas of concern include exposure to bisphenol A (BPA) in household plastics and flame retardant chemicals in fabrics.

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Several factors could change the tide of education on the impact of toxins.

Lead study author Dr. Naomi Stotland, an associate professor in the department of obstetrics, gynecology, and reproductive sciences at UCSF, sees progress at her own university hospital, and hopes others will follow suit. Top researchers in reproductive health and environmental science are incorporating these topics into the core curriculum for medical students in an effort to create a “big picture talk on environmental exposure,” Stotland said.

Charles Margulis, communications director at the Center for Environmental Health in Oakland, Calif., believes that the greatest impact will come with increased federal regulation.

“When you have government regulations that are based on the idea that chemicals are safe until proven harmful, everything follows from that,” he said. “We don’t start regulating chemicals until we see people getting sick.”

It’s tough to test and regulate the roughly 80,000 chemicals on the market, but researchers are beginning to make headway.

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While doctors don’t yet know the impacts of all toxins, reminding patients about where they might be lurking is a key part of the holistic health discussion. This is especially true for pregnant women. A substance that might not typically affect a woman could still harm a developing embryo.

Dr. Brett Worly, an OB-GYN at Ohio State University’s Wexner Medical Center in Columbus, says it’s crucial that he knows whether his patients are exposed to any potentially harmful toxins, such as pesticides, mold, or industrial chemicals, at home or work.

“I talk to my patients about their professions or what their role outside the home is,” he said.

He also points patients to material safety data sheets, which detail exposure risks for different chemicals and ways to avoid those materials.

Worly recommends that patients write down questions before they come in for appointments to ensure that all their concerns are addressed, and write down the answers in order to remember them later. As the UCSF study shows, the dangers of environmental toxin exposure should be among the question doctors ask at prenatal visits.

Women who work in fields where they are exposed to toxins, or in lab settings with heavy chemical use, should take special care to ask about avoiding contact with these potentially harmful toxins.

The Toxic Matters brochure produced by UCSF was created specifically for pregnant women and their families to explain environmental toxins and provide tips for avoiding them. Other consumer resources, such as the Environmental Working Group’s Dirty Dozen list, which outlines fruits and vegetables that may contain pesticide residue, could also be helpful.

All consumers, pregnant or not, can take steps to reducing their exposure to various toxins.

“It’s not possible to make them zero, but the point is to try to reduce our exposure as much as it is feasible and practical,” Stotland said.