Women entering their child-bearing years are repeatedly told to take care of themselves and their health, even if they're not yet (or ever) looking to get pregnant. The thinking behind it is "just in case." Just in case you get pregnant, your baby will be at lower risk for pre-term birth, small birth-weight and other negative birth and newborn outcomes.
But new findings in autism research might mean that health warning should come well before the child-bearing years. Like, a generation before.
A University of Bristol epidemiological study of a cohort of kids boarn in the 1990s, found that women whose grandmothers—their mothers' mothers—smoked during pregnancy gave birth to kids at higher risk for a diagnosis on the autism spectrum.
Grandma! Enough with the bad habits!
Researchers analyzed 14,500 participants registered in the U.K. birth cohort and found that girls whose maternal grandmother smoked during pregnancy were 67 percent more likely to display certain traits linked to autism, such as poor social communication skills and repetitive behaviors.
The data suggests that developing eggs of females, while still in the womb, may be affected when exposed to cigarette smoke, which can negatively influence the development of her own children.
"To date, research into the causes of autism has been limited to studying maternal or paternal exposures during pregnancy," said Alycia Halladay, chief science officer at the Autism Science Foundation in the U.S. "By utilizing a birth cohort in the United Kingdom [Children of the 90s], scientists are able to go back a generation to examine the role of grandparental exposures, presumably through germ line mutations and epigenetic modifications."
'We already know that protecting a baby from tobacco smoke is one of the best things a woman can do to give her child a healthy start in life.'
The findings were published in Scientific Reports recently as part of an ongoing investigation of the effects that maternal and paternal grandmother's smoking during pregnancy has on the development of grandchildren.
Though past studies of maternal smoking during pregnancy and ASD in children have been inconclusive, researchers were able to rule out additional explanations for their results. Even so, they emphasized that other factors, including genetic variation, can affect an individual's chances of developing ASD.
"We already know that protecting a baby from tobacco smoke is one of the best things a woman can do to give her child a healthy start in life," Jean Golding, one of the paper's authors, said. "Now we've found that not smoking during pregnancy could also give their future grandchildren a better start too."
'The associations we observe raise intriguing issues on possible transgenerational influences in autism.'
Despite conclusions from this discovery, scientists still have a long way to go when it comes to unraveling ASD.
"We still do not know why many children develop autism and behaviours linked to it," Dr. Dheeraj Rai, another author, said. "The associations we observe raise intriguing issues on possible transgenerational influences in autism. Future research will help understand the meaning and mechanisms behind these findings."
Next on the chopping block: Concentrating on molecular changes to see whether the same associations are present in other groups of people.
We may not have all the answers we are looking for as parents, but everyday science offers a little more and, eventually—together—we will get there. Until then, let’s agree to trade those cigarettes in for some knitting needles and enjoy the ride before it's too late.