Following on the heels of the controversy linking autism to vaccines a new study in the Journal of Pediatrics has identified another possible cause. The study reveals that children conceived one right after the other–less than 12 months after the birth of a sibling–have a three times greater risk of developing autism.
Columbia University researchers examined medical records of 662,730 second-born children. What they discovered was a spike in the risk of autism that correlated to how close these children were born to their older siblings. The mother’s age and education, as well as the baby’s birth weight and other factors were of no significance in the findings.
For babies born 12 to 23 months after the birth of an older sibling the risk was doubled and for those conceived 24 to 35 months later the risk was one quarter as high.
The researchers say they don’t know what causes this increased risk but the correlation is obvious. Having children back to back as been linked to other health issues as well, such as premature delivery, low birth weight, and schizophrenia. A possible explanation is that the mother’s uterus needs time to recover from the strains of pregnancy especially when it comes to replenishing stores of nutrients such as iron and folate. It could be that second born children don’t receive enough of these essential brain nutrients when they’re conceived too early.
Another theory is that parents may be more aware of normal developmental stages in a second child so that an earlier diagnosis of autism as possible.
If improper nutrition is behind this spike, this could be good news for fighting autism. It could be as simple as providing additional supplements to the mother. However this new study is applicable to only a few cases so it’s obviously not the only cause of the disorder.What does this mean to parents when planning a family?
It depends. Older women increase their chances of having children with birth defects and birth complications the longer they wait between pregnancies. That could outweigh concerns of the yet unsubstantiated risk for autism. Some experts recommend waiting three years between pregnancies to minimize the risk of complications.
Other studies show a link between the jump in autism and vitamin D deficiency during pregnancy. The brain tissue in developing fetuses have vitamin D receptors and when activated they increase nerve growth in the brain. The vitamin D deficiency could have a negative effect on this nerve growth.
Some experts believe that such a deficiency could be one of the largest contributing factors to autism. For this reason they recommend pregnant mothers should get their vitamin D levels tested. Supplements may be necessary if natural sun exposure isn’t enough.
Chances are that until research leads to a definitive cause, everything from cell phones to molds will be linked to autism. In the meantime, expectant mothers should do all they can to avoid exposing their developing baby to any substance that is known to be hazardous to adults. If it can cause damage outside the uterus, it could cause damage inside, too.