Hot on the heels of last month's fertility scaremongering about ovarian reserve came a new scare for women planning to start late-in-life families, this one about autism. Once again, reporting on it ignored essential facts and skewed the takeaway.
The recent UCDavis study exploring the effect of parental age on the likelihood that a child would be autistic made headlines. "Study: Older Moms Risk Autism in Children" Time told us, reprinting the AP story; "Autism linked to older moms," echoed many others. That's the line the 28-year-old I ran into that day parroted back to me, worriedly. One NY Times blogger directly linked discussion of the increased odds for autism with maternal age to a questionnaire about the best age for having kids. Talk about a (mis)leading question.
But while the study, based on 4.9 million California births in the 1990s, documented that the risk of autism increases with maternal age by 51 percent and that paternal age is also a factor, few of the reports asked the key question "51 percent of what"? If the risk at 25 is low to begin with, then adding on another 51 percent doesn't change things much.
And it is low: less than one quarter of one percent of the 25 to 29 year olds in the study had an autistic child, and while the odds increased by 51 percent for women 40 and over, that meant that less than one half of one percent of the older women had autistic kids. As Janie Shelton the study's lead author put it, though they have a very slightly greater chance than younger women, "older women have a dramatically small chance of having a child with autism." But that was not the takeaway for most readers.
The authors also found that advanced maternal age was the cause of just 4.6 percent of the 600 percent rise in reported cases of autism in the 1990s. That means that less than one percent of the total autism rise was due to maternal age.
While the headlines are technically accurate, they create a major false impression. Older mothers do not regularly have autistic children, though some do, as do some mothers at all ages. Genetics as well as environmental factors, many of which are currently hotly disputed, play much bigger roles in causation. And older mothers may simply be better at navigating the complex system required to get a state diagnosis.
Missing Context
What's missing in this story, as in the ovarian reserve story, is context. Saying that maternal age creates a 51 percent rise in risk of autism at 40 means nothing if you don't also explain what the original risk was. Talking about an abstract proportion of eggs a woman has without discussing how many are actually needed is similarly pointless. Unless the point is to confuse people, create anxiety, or push them to have babies whether or not they feel ready for them.
A few media outlets were more even-handed on the autism story (the LA Times and CNN were the most thorough of the stories I saw--though their headlines still spread skew). But overall, delay of motherhood, by a few years or by many--a trend that is overwhelmingly responsible for allowing women to invest in their educations, climb career ladders and begin to have a role in business and government policymaking --gets a bum rap in this kind of coverage.
Selective presentation of "facts" creates big misunderstandings, in the fertility realm as in all realms. Time for reporters to do more than rehash numbers that come in over the wire, and actually put the data in perspective. Until they do, time for women to be skeptical of everything they hear about fertility on the news - if they aren't already.
Elizabeth Gregory directs the Women's Studies Program at the University of Houston and is the author of Ready: Why Women Are Embracing the New Later Motherhood (Basic Books, 2008). She blogs about the politics and economics of motherhood and women's work at www.domesticproduct.net
This originally appeared on RH Reality Check.