Children born soon after a older sibling may be at a higher risk of autism, finds a new study in the February issue of Pediatrics.
Researchers at Columbia University examined the records of over 600,000 sibling pairs and found that in instances where the pregnancies were less than 36 months apart, the children showed a higher incidence of autism. The risk was highest when there was less than a year between pregnancies.
The study showed that 37.9 percent of the children diagnosed with autism had been born within a year of their sibling, compared to only 23.5 percent of children without an autism diagnosis.
The study, however, is only a first step and not yet conclusive. Researchers will now need to duplicate the findings, and if the link is confirmed, the search will begin to uncover the underlying cause.
Some scientists hypothesize that the higher risk may be due to a depletion of the mother’s nutrients after the first pregnancy, as well as a higher level of stress hormone. Although the theory remains untested, it is important for women having close pregnancies to ensure that they are receiving the best prenatal care possible.