​Vitamins A and D decrease the risk for schizophrenia and autism. Prenatal vitamins already contain the maximum safe amount of each.
Omega-3 fatty acids (DHA, Fish Oil) during early pregnancy increases the risk for schizophrenia and increases symptoms of attention deficit hyperactivity disorder, but in later pregnancy it decreases childhood wheezing, an early form of asthma, and premature birth. Most prenatal vitamins have some omega-3 fatty acid, but you need to take them despite that. The amount of omega-3 fatty acid is relatively low.
Folate supplements, especially when begun before birth, decrease spina bifida and cleft palate. They also improve the baby’s general mental ability and decrease problems with attention
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Read more: Robert Freedman, Sharon K. Hunter, M. Camille Hoffman.
Prenatal Primary Prevention of Mental Illness by Micronutrient Supplements in Pregnancy
American Journal of Psychiatry 2018 text Table 3 is from this article.
Link to Video from Dr. Hoffman.

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