A new study published in the journal Epidemiology found that women who took prenatal vitamins — particularly during the time of conception — decreased their child's risk of developing autism by almost 50 percent.  

For the study, researchers gathered data from mom/child pairs in California. They used information from the Childhood Autism Risks from Genetics and the Environment (CHARGE) study, a study of preschool children with autism, to identify children with autism. Autism was confirmed in the children based on results from two standardized clinical assessments. The children without autism were identified from state birth records.

Researchers looked at data for children who were 2 to 5 years old. They asked the mothers about their use of prenatal vitamins, multivitamins, other nutritional supplements and dry cereal to measure their prenatal intake of nutrients like folate that are important in early neurodevelopment. They evaluated the risk of autism when the mother took prenatal vitamins before conception, later in pregnancy and regularly during pregnancy.

Mothers who took prenatal vitamins before conception and during the first month of pregnancy had nearly half the risk of having a child with autism when compared to mothers who did not take prenatal vitamins during this pregnancy stage. For women who took prenatal vitamins only later in pregnancy, there was not a detectable difference in risk.

And not just any vitamin would do. Researchers found no change in risk with standard multivitamin use. It was prenatal vitamins — those that typically contain more iron, vitamins B6 and B12 and twice as much folic acid — that reduced the child's risk.

The bottom line: If you're thinking about getting pregnant, (or are otherwise engaging in behaviors that could potentially lead to pregnancy) go ahead and start taking those prenatal vitamins. They are good for you, and could be really good for your future baby.

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