Mothers exposed to higher traces of a common plastic chemical are more likely to give birth to autistic boys, a new study finds.
Research found that developing boys exposed to trace amounts of bisphenol A (BPA) in the womb were six times more likely to receive a full diagnosis by the age of 11.
They were also more likely to exhibit autistic symptoms by age 2.
Seventy pairs of young mothers were followed by experts from the Florey in Melbourne, Australia, one of the most renowned brain development centers in the world. The evaluation period lasted a decade.
“Some studies have already shown that exposure to plastic chemicals during pregnancy is associated with later autism in offspring,” said Anne-Louise Ponsonby, professor and lead researcher, in a statement.
She believes the work will contribute to a better understanding of “part of the autism puzzle.”
Getty Images
BPA is used to harden plastics found in household items such as food containers, glasses and water bottles.
Broken down into microplastics, these substances enter the human body through the accidental absorption of plastic products.
BPA significantly impairs the healthy development of the baby in the womb by blocking the mother’s aromatase, an enzyme particularly important for the development of male fetuses.
It is known that restricted maternal aromatase inhibitors have profound implications on gestational development.
Why doesn’t the same phenomenon affect young girls? It is known that a deficiency in healthy amounts of the enzyme affects girls later, and in a physical rather than neurological way, through delayed development of secondary sexual characteristics and baldness.
The team fears that the ubiquity of plastic products will make it nearly impossible to eliminate BPA.
“We all ingest plastic chemicals in many ways: by ingesting plastic food and drink packaging, inhaling home improvement fumes and through the skin from sources such as cosmetics,” Ponsonby said.
“These chemicals enter our bodies in multiple ways, so it’s not surprising that BPA was present in a large proportion of the female urine samples we studied. It’s important for us to understand how these plastics affect our health.”
Getty Images
Following this, Ponsonby and his team decided to study this theory in more detail using mice.
They treated each of them with a rodent-sized dose and saw distinct behavioral changes.
“We found that BPA suppresses the aromatase enzyme and is associated with anatomical, neurological and behavioral changes in male mice that may be consistent with autism spectrum disorder,” said Dr. Wah Chih Boon, a research associate, in a statement.
A type of fatty acid called 10-Hydroxy-2-decenoic acid has been shown to be effective in reversing some of the above side effects in each animal.
“Further studies are needed to determine whether this potential treatment could be applied to humans,” she added.
These findings now contribute to public safety regulators regarding exposure to manufactured chemicals, including plastic chemicals, during pregnancy and early life.
Getty Images
However, the consensus among other specialists in the field is mixed.
David Skuse, professor at UCL’s Institute of Child Health, agrees that more needs to be done to understand the dangerous substances that interfere with hormone production during child development.
“I am certainly concerned about the environmental impact of endocrine disruptors – it is indeed an important area of research,” he said. Newsweek.
Although researchers have a “plausible set of hypotheses,” he says, it’s important to remember that “association does not equal causation.”
He disagrees with the idea that mice are the appropriate subjects for undertaking more in-depth observations.
“Men and women with ASD have similar levels of social communication impairment, both qualitatively and quantitatively. It is impossible to measure the subtleties of human social communication from a mouse model.”
Dr Alex Tsompanidis specialises in the role of steroid hormones in neurodevelopment at the University of Cambridge’s Autism Centre.
The theme of this research echoes much of his own work. Even so, he believes the study would need to be replicated on a larger scale, several times, before any real conclusions can be drawn.
“However, (the study) should be replicated in larger, independent cohorts. We know that the cause of autism is multifactorial and also involves hereditary/genetic factors,” he said. Newsweek.
“I think it is important to emphasize that we do not view autism as a disorder that needs to be prevented or cured, but as a condition that contributes to the neurodiversity of human societies. Therefore, any clinical potential needs to be carefully considered and targeted towards improving the lives and health of autistic people.”
Do you have any idea about a scientific story that Newsweek should be covered? Have a question about microplastics? Let us know at science@newsweek.com.
The references
Novakovic, B., Herbstman, J.B., Wang, S., Guo, J., Chia, J., Tran, N.T., Hwang, S.E., Britt, K., Chen, F., Kim, T.H., Reid, C.A., … Boon, W.C. (2024). Male autism spectrum disorder is linked to brain aromatase disruption by prenatal BPA in multimodal studies and 10HDA ameliorates the associated mouse phenotype. Nature Communications15(1), 6367. https://doi.org/10.1038/s41467-024-48897-8
