Autism Risk Higher With Closely-Spaced Pregnancies
Second children who are conceived within a year of their older sibling's birth were more than three times more likely to be diagnosed with autism than those conceived more than three years after their older sibling was born, according to an article in the journal Pediatrics.
Researchers looked at records of babies born in California between 1992 and 2002 and examined the odds of autism in more than 660,000 second children. They found that the further apart pregnancies were, the lower the risk of autism in the second child, the article says. Compared to children conceived more than three years after their older sibling's birth, children conceived 12 to 23 months after a previous birth were twice as likely to have been diagnosed with autism, and children conceived after a 24- to 35-month gap were one and a quarter times more likely to have been given that diagnosis.
The study's authors don't know why pregnancy timing and autism are linked, but they suggested some factors that may be to blame, although they didn't test for them. Some of the possible culprits are depleted levels of nutrients, such as folate and iron, and higher stress levels, the article says. The results accounted for low birth weight, premature births and the age of the parents, the article says.
The finding is particularly important because the number of babies born within two years of their older sibling is on the rise, up from 11 percent in 1992 to 18 percent in 2002, the authors write.
Start by teaching him that it is safe to do so.