Do Prenatal Vitamins decrease Autism?

UC Davis has recently conduced a study regarding the use of prenatal vitamins.  While autism is multifactorial and a result of several possibly combinations, could taking a prenatal vitamin decrease the risk of autism?

This study was conducted in partnership with the Markers of Autism Risk in Babies: Learning Early Signs (MARBLES) and consisted of 241 younger siblings of children with autism spectrum disorders.  The study found that taking a prenatal vitamin especially in the first trimester or even before getting pregnant could reduce the risk of autism.  While the study is preliminary, it does shed some light on the importance of prenatal vitamins in pregnancy especially during the embryonic age when the baby is forming. 

While the exact benefit and vitamin has not yet been isolated yet, we do know that most prenatal vitamins tend to contain folate, zinc and iodine. In addition the usually contain several, if not all, B vitamins including vitamin B12 

For further reference the journal can be found in JAMA Psychiatry 2019.  Schmidt R, Iosif A, Guerrero-Angel E, Ozonoff S. Association of maternal prenatal vitamin use with risk for autism spectrum disorder recurrence in young siblings. JAMA Psychiatry 2019 Feb 27