It’s parental instinct to want to make a child’s world as safe and normal as possible. And when that world is different from the one most other children live in, parents want to know why.
When a pediatrician’s patient lives in the world of autism, explaining the whys and whats to the parents is particularly daunting. Writing in the New York Times recently, Dr. Perri Klass addressed how she relates to parents of autistic children who want to know the cause and, for prospective parents, how they can reduce the risk for children they’re planning to have.
“[A]lthough there is more research in this area than ever before,” she writes, “it sometimes feels as if it’s getting harder, not easier, to provide answers that do justice to the evidence and also offer practical guidance.”
Autism is a complex disorder that research has shown is driven by both genetic and environmental factors. As Klass describes, “Genes matter, but we usually can’t tell how. Environmental exposures matter, but we usually don’t know which.”
Not much there for parents to work with.
A study of autism in twins showed that fraternal twins were both likely to have the disorder, which seems to compromise the strength of the genetic component (since fraternal twins share fewer genes than identical twins).
A couple of generations ago, when ignorance about all mental disorders was evident far more than common sense, autism was blamed on remote parenting. More recently, a noisy campaign was based on fake science supposedly indicating an association between childhood vaccinations and autism, a theory that has been wholly discredited.
But the genetic influences have been proved scientifically sound, and autism spectrum disorder has been described by the American Psychiatric Association as “among the most heritable of psychiatric disorders.”
This evolution of understanding has led scientists to accept that autism results both from genetic predisposition and from environmental influence. But “environment” is a fluid concept.
As one researcher quoted by Klass put it, it’s “everything that’s not the inherited DNA.” Parents might wonder about the chemical ingredients of the placenta’s soup, about the mother’s nutritional profile, her stress level, about the caustic cleaning products under the sink … They’re all part of a developing fetus’s environment.
According to Klass, “The causal links most strongly supported by research include rubella (measles) infection during pregnancy and prenatal exposure to medications like thalidomide and valproic acid, an anti-seizure drug.” Air pollution and exposure to pesticides have an association with autism, but there’s no evidence of causality.
Phthalates, which are chemicals found in flexible plastic products such as shower curtains and other household furnishings such as carpet and shampoo, can leach out in microscopic amounts and disrupt a variety of developmental processes, including brain development. But, again, they haven’t been shown to be a cause of autism, only as an association with its symptoms.
Bottom line: Autism is a custom-made disorder, and probably the result of several factors.
“So it’s hard — and frustrating — to offer prospective parents advice about avoiding risks we still can’t clearly identify,” Klass observes, “and factors that may differ from family to family.”
You can’t completely sanitize your environment, you can’t turn your uterus into a scientific “clean” room — potential toxins are simply a part life. But Klass does offer prospective parents concerned about autism some advice that’s more a prescription of common sense than a prophylactic:
- Take prenatal vitamins before trying to conceive.
- Ensure your immunizations are up to date.
- Get good prenatal care.
- Discuss the risks and benefits of any medications you take with your doctor.
- Avoid pesticides.
- Don’t microwave food plastic containers.
- Use fragrance-free personal products.
“Still, Klass concludes, “it’s hard to talk about this without terrifying parents. And I wonder if in giving advice about prevention, we risk repeating the errors of the past, making parents feel they’re to blame for a child’s autism because they failed to micromanage an environment full of complex agents with potential to interact with fetal genes in a range of damaging but poorly understood disruptions.”