Phthalates Exposure in Womb Linked to Autistic Traits in Boys
By George Citroner
- Exposure to phthalates was associated with autism traits in boys (but not girls) between ages 3 and 4 years, according to a new study.
- However, the risk was diminished in women who took folic acid during their pregnancy.
- This study is the first to find that folic acid supplements provide a protective effect from phthalates.
Exposure in the womb to a group of endocrine-disrupting chemicals called phthalates was associated with autism traits in boys (but not girls) between ages 3 and 4 years, according to a new study.
However, fewer of these traits were observed in boys whose mothers took the recommended amount of folic acid during the first trimester, the findings suggest.
"Very few studies looked at autism and its associated traits, with inconsistent findings. We tried to look at this question in a large sample from a Canadian cohort that was designed specifically to look at potential developmental effects of exposure to environmental chemicals," lead author Youssef Oulhote, assistant professor of biostatistics and epidemiology at UMass Amherst's School of Public Health & Health Sciences, told Healthline.
Phthalates are commonly used in many products, including soap and cosmetics.
Mothers Recruited From the MIREC Study
Oulhote and team enrolled 2,001 Canadian women with an average age of 33 who were in their first trimester of pregnancy between 2008 and 2011. Less than 10 percent of the women reported regularly drinking or smoking during pregnancy.
All the participants were recruited from the Maternal-Infant Research on Environmental Chemicals (MIREC), a longitudinal pregnancy cohort study conducted in Canada.
Researchers collected information from questionnaires, medical charts, and maternal blood and urine specimens during pregnancy and at delivery.
Concentrations of 11 phthalate monoester metabolites were measured in first trimester urine samples at the Toxicology Centre of the Quebec Institute of Public Health.
"We had several limitations, the most important one being that these phthalates exposures may vary in time, and therefore future studies should consider this and try to measure these phthalates at multiple time points in pregnancy," Oulhote said.
Greater Phthalate Exposure Associated With Autism Traits
Researchers performed neuropsychological assessments on 610 of the children born when they were between 3 and 4 years of age.
This included the Social Responsiveness Scale-2 (SRS-2), a measure of autism traits and social impairment. A higher score means more autism traits are present.
"We looked at autistic traits, not an autism diagnosis, which would have required a very large sample size or a different study design given the rarity of ASD. However, looking at autistic traits provides a very good idea about how these traits occur at a population level," Oulhote explained.
Researchers found that greater concentrations of phthalate chemicals in a mother's urine samples were associated with increases in SRS scores, but only in children whose mothers didn't take a recommended daily folic acid dose (400 micrograms) during their first trimester.
Folic Acid Is Key
This study is the first to find that folic acid supplements provide a protective effect from phthalates. Oulhote also believes that folic acid supplements might block the effects of other toxic chemicals.
"The most surprising and important finding was how adequate important folic acid supplementation was in offsetting the potential effects of phthalates on autistic traits," Oulhote said.
Previous studies have shown folic acid is associated with reduced chance of autism spectrum disorder that's caused by prenatal exposure to pesticides and air pollutants.
Phthalates Affect Health in Many Ways
Phthalates are a group of chemicals used to make plastics more flexible and harder to break, often called plasticizers.
They're also used as dissolving agents for other materials, according to the Centers for Disease Control and Prevention.
Previous research has shown that children whose mothers are exposed to phthalates during pregnancy were more likely to have motor skill issues, and another found that these children exposed during pregnancy had problems with language development.
Phthalates Are Almost Everywhere
These chemicals are in hundreds of products, including vinyl flooring, adhesives, detergents, lubricating oils, automotive plastics, raincoats, and personal care products, like:
- hairs sprays
- nail polish
Phthalates are also an ingredient in polyvinyl chloride (PVC) plastics, which are used to make plastic packaging film and sheets, garden hoses, blood storage containers, medical tubing, and some children's toys.
Phthalates are almost impossible to avoid in our modern environment, but there are ways to minimize your exposure.
While the Food and Drug Administration mandates that phthalates be listed in the ingredients of personal care products, they don't have to be if they're added as part of the fragrance.
Although companies will label their products "phthalate free," it may be best to call them up and make sure.
New mothers can take simple measures to keep baby safe.
"Once the baby is born, continue to be mindful about chemicals that can cause harm. Look for fragrance-free products that are as all-natural as possible. Keep up with DIY, including for cleaning products, and limit plastics in the house, especially baby bottles and toys," wrote Claire McCarthy, MD, a faculty editor for Harvard Health Publishing, in the Harvard Health Blog.
The Bottom Line
New research finds pregnant women exposed to phthalate chemicals during pregnancy can give birth to boys who show traits of autism.
However, the children of those mothers who took the recommended amount of folic acid showed far less traits.
This is the first study to find that folic acid supplements can protect unborn children from effects of phthalates.
Phthalates are everywhere in our environment, but there are ways to reduce your exposure, including avoiding canned foods, certain plastics, and personal products that contain this class of chemical.
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