Recent research has given us further insight into what could be causing autism spectrum disorder (ASD), such as pesticides or just having an older father. There are even studies that have correlated risk factors as early as pregnancy, like raised hormone levels or infections in the placenta, to a child having the developmental disorder.
However, since the actual cause of autism has yet to be discovered, just having the presence of any of these factors in the womb, isn’t concrete enough to know if the child will have ASD during pregnancy.
That means, as of now, there isn’t a way to test for autism during pregnancy. But that doesn’t mean scientists aren’t trying!
Scientists have been studying various parts of the body in an attempt to discover where autism may originate.
The Prefrontal Cortex Studies
In 2014, a study was published in the New England Journal of Medicine claiming that scientists were able to find differences in the brains of autistic children as young as the second trimester of pregnancy.
The study explained, “autism involves early brain overgrowth and dysfunction, which is most strongly evident in the prefrontal cortex. As assessed on pathological analysis, an excess of neurons in the prefrontal cortex among children with autism signals a disturbance in prenatal development and may be concomitant with abnormal cell type and laminar development.”
So, to examine the parts of the brain that they were interested in, the scientists used RNA and other cell-type molecular markers to check for markers of neurons and glia, along with other genes that have been correlated to cause autism, in several sections of the brain from postmortem samples of children with autism spectrum disorder, and without, between the ages of 2 and 15 years old.
In the end, they identified “discrete patches of disorganized cortex in the majority of postmortem samples obtained from young autistic children that we examined. These patches occurred in regions mediating the functions that are disturbed in autism: social, emotional, communication, and language functions. Such abnormalities may represent a common set of developmental neuropathological features that underlie autism and probably result from dysregulation of layer formation and layer-specific neuronal differentiation at prenatal developmental stages.”
The Placenta Studies
Judy Van de Water, a professor at the University of California Davis, explains how recent studies are looking at infections in the placenta for possible autism clues.
During a pregnancy, the mother’s immune system changes. Cytotoxic T cells are suppressed, because they could potentially destroy the placenta. While B cells, which are protective and produce antibodies, are still doing their regularly programmed job. These cells, mixed with others, are trying to send the appropriate signals to each other to help maintain the mother’s immune system for her placenta, and fetus! However, it turns out this interaction could be affecting the fetus in ways scientists were unaware of.
“The placental-uterine boundary is famously the fetus’ lifeline. Nutrients cross from the mother to her fetus across this channel, and wastes flow back for removal. A better understanding of what happens at this interface may reveal how immune activation disrupts fetal brain development,” Van de Water writes. “A better understanding of what happens at this interface — both under ordinary circumstances and after maternal immune activation — may reveal how immune activation disrupts fetal brain development.”
According to the article, other work suggests that “certain potentially damaging molecules secreted by activated immune cells, such as interleukin-6, can make their way to the placenta or the fetus, or both, and alter the way the brain develops. If this is true, efforts to block these secreted factors during pregnancy might help protect the fetus.”
In short, researchers still need to understand all the aspects of the maternal immune system to fully understand what’s going on between a pregnant woman’s immune system and autism spectrum disorder. But, Van de Water’s work could be propelling the way to more insight on how a genetic predisposition could lead to autism following a maternal infection.
Autism in the Blood
Finally, could we see autism in pregnant mothers by looking at their blood? A paper published in 2018 in the journal Research in Autism Spectrum Disorders claims they can predict autism whether a pregnant mother has will increased risk of having a child with ASD with 90% accuracy.
“In this study, metabolites of the folate-dependent transmethylation and transsulfuration biochemical pathways of pregnant mothers were measured to determine whether or not the risk of having a child with autism could be predicted by her metabolic profile. Pregnant mothers who have had a child with autism before were separated into two groups based on the diagnosis of their child, whether the child has autism or not. Then these mothers were compared to a group of control mothers who have not had a child with autism before,” they explain.
The researchers concluded that it was not possible to determine if a child will be diagnosed with ASD during pregnancy, but they did find that the differences in “plasma metabolites are indicative of the relative risk (18.7 vs 1.7%) for having a child with ASD.”
What About Epigenetics?
Overall, it’s clear that, while studies are promising for the future, right now there is no test during pregnancy for autism spectrum disorder.
As some are struggling to find a genetic cause for ASD, others are turning toward potential environmental causes. Parents Magazine points out that “while you can’t do much to change genetics, you can alter your exposure to certain environmental factors that have shown a link to ASD.”
It begs the question, what about epigenetics?
Recent research has shown that saliva can be useful for detecting autism spectrum disorder in children. Instead of looking at DNA, as many of the ongoing studies currently are, this study is looking at the relationship of RNA molecules in the saliva, called microRNA, as well as the microbiome, and autism.
Albeit, this saliva test for autism doesn’t work in the womb either. But it can be used as young as 18 months old, which is when the American Academy of Pediatrics recommends screening for autism. So for expectant mothers who may be higher risk for autism spectrum disorder, this could be the biological test they need to jumpstart an early diagnosis for their child.
So where does that leave expectant mothers? Science is still uncertain. But it’s universally agreed that it’s best for pregnant women to take care of themselves as best as they can, avoid harmful, certain risk factors, and take each day one step at a time.
In the meantime, there is a saliva autism test for children ages 18 months through 6 years of age, learn more at ClarifiASD.com.