We know that environmental factors – including exposure to certain toxic substances during pregnancy – can increase the risk of autism. (See “What do scientists mean when they talk about ‘environmental factors’ that cause autism?”)
It’s important to distinguish increased risk from cause. In most cases, autism results from multiple factors in addition to genetic predisposition. These can include a pregnant woman’s exposure to certain chemicals such as pesticides and phthalates (commonly found in plastics) and certain drugs such as terbutaline (used to stop premature labor), valproic acid (to control seizures) and some antipsychotics and mood stabilizers.
Importantly, in the case of medications, any possible increased risk of autism must be balanced against a woman’s medical needs. Remember, your health can likewise affect your pregnancy and the health of future children. (Also see, “Can my taking medication during pregnancy cause autism in my baby.”
We have much more to learn about the environmental factors that increase autism risk. And we can’t say that avoiding one particular exposure means reducing risk of ASD for a particular individual. However, we know that exposure to certain toxic substances is associated with increased risk for a number of developmental disorders. So we can recommend some practical, protective steps that women can take before or during pregnancy to these exposures.
Recommendations to consider if you’re pregnant or trying to conceive:
The American College of Obstetricians and Gynecologists, the Royal College of Obstetricians and Gynecologists and other authorities endorse the following recommendations:
1. Discuss medications with your healthcare provider. In particular, discuss risks associated with terbutaline, valproic acid (valproate), over-the-counter painkillers, prenatal vitamins, antipsychotics and mood stabilizers.
2. Ask your doctor about folic acid. Research suggests that folic acid supplements – taken before and during pregnancy – reduce the risk of autism. (Also see “Evidence that Folic Acid Reduces Autism Risk” and “More about Prenatal Folic Acid and Autism.”)
3. Avoid cigarette smoke and alcohol. Both can have adverse effects on fetal development as well as long-term health of both mother and child.
4. Eat plenty of fresh produce, but wash it before eating. Eating plenty of fresh, unprocessed fruit and vegetables is highly recommended during pregnancy. Just be sure to wash thoroughly to reduce possible pesticide or microbial contamination. NOTE: The Environmental Working Group just published an analysis of the fruits and vegetables with highest levels of pesticides. Make extra sure to wash this "Dirty Dozen" thoroughly.
5. Cut down on packaged foods. Some packaged foods – such as microwave/oven-ready meals – leach chemicals into food. These chemicals can include endocrine-disrupting chemicals such as BPA and phthalates. In particular, avoid plastics with the recycling codes #3, #4 and #7.
6. Eliminate or limit to once a week your consumption to oily fish and tuna. Oily fish can accumulate dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB) in their fat tissues. Certain other fish such as tuna tend to accumulate mercury and lead.
7. Limit your use of personal care products (moisturizers, body wash, perfume, etc.) with strong scents and artificial ingredients. Visit this Parents.com webpage for some creative “safer swaps” such as fragrance-free products.
8. While pregnant or breastfeeding, reduce or avoid your exposure to fumes from new household furniture, fabrics, non-stick frying pans and cars; pesticides, fungicides, fresh paint or solvents. Avoiding these products will reduce your exposure to potentially toxic chemicals such as perfluorinated compounds (PFCs).
9. Remember that “natural” doesn’t necessarily mean safe during pregnancy. This is particularly true of over-the-counter “alternative” medications and supplements. Few have been tested for safety during pregnancy.
10. Fill out an environmental exposure history questionnaire and bring it to your health care provider: http://prhe.ucsf.edu/prhe/pdfs/Huffling%20prenatal-preconception%20assessment.pdf
Research continues ….
Autism Speaks funds research on a wide range of environmental risk factors for autism. The more we learn about how these exposures influence affect brain development, the better we can help individuals and families affected by autism.
If you want to learn more, here are some recent studies looking into factors that appear to increase autism-risk during pregnancy:
Got more questions? Send them to GotQuestions@autismspeaks.com. And thanks to our passionate community of families and supporters for helping advance our understanding of autism, its treatment and how best to support all those on the autism spectrum.
Sources of Information: