Does Vitamin Use In Early Pregnancy & Autism Risk

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Medically reviewed by Kimberly Langdon, MD

Prenatal Vitamins Linked To Autism

Autism or Autism Spectrum Disorder (ASD) is typically characterized by problems in communication, social interaction, and restricted, repetitive behavior. It is a neurodevelopmental disorder with global instances on the rise. 

Studies have shown that the health and diet of the mother during early pregnancy have a major role in the neurodevelopmental process of the fetus. Prenatal vitamin supplementation can affect the development of ASD in the baby.

Is there a link between prenatal vitamins and autism? Can prenatal vitamins increase the risk of ASD or reduce it? In this article, we will answer these questions and discuss some important facts about prenatal vitamin supplementation and autism.     

Prenatal vitamins linked to autism 

Multiple studies[1] have established a strong link between prenatal vitamins and autism. An important case-control cohort study was performed with 45,300 Israeli children born between 1st January, 2003 and 31st December, 2007 to establish the relationship between prenatal multivitamin exposure and risk of ASD. The children were followed up from birth till 26th January, 2015. 1.3% children from this group were diagnosed with ASD. The study concluded[2], maternal exposure to Folic Acid and multivitamins is associated with a reduced risk of ASD in the offspring compared to the children of mothers who did not take the multivitamins. 

Maternal prenatal vitamin supplementation near conception and during early pregnancy has been linked with decreased autism risk in children[3] with an older sibling with ASD. It reduces the chance of autism spectrum disorder recurrence in high-risk families. 

Children whose mothers had taken prenatal vitamins particularly during the first month of pregnancy were at less risk of ASD[4] compared to the children whose mothers didn’t take the supplement in that particular period. These results were consistent with many earlier reports indicating that folic acid and multivitamin supplementation before conception and during the early stages of pregnancy can protect against autism.     

With the increase in the number of ASD-affected children across the world, these findings can be helpful to reduce the risk. Since the mid-1990s government and health organizations from around the world have adopted policies to increase folate intake before and during pregnancy to reduce the risk of having a baby with a brain or spinal cord defect[5] or neural tube defect (NTD).  

However, it is important to note, taking prenatal vitamins and folic acid supports proper brain development in the fetus, reduces the risk of ASD and other neural defects in the baby but does not eliminate it, as there can be more than one factor in play. 

Can prenatal vitamins increase the risk of ASD?   

The positive correlation between folic acid consumption by the mother and reduced risk of ASD in the infant has naturally prompted medical professionals to suggest it before and during pregnancy along with other prenatal vitamins. 

The concern arises from one research[6] that studied maternal blood folate status during early pregnancy and the occurrence of autism spectrum disorder in the offspring. The study found evidence of a weak positive association between high serum folate concentrate in the mother and increased occurrence of ASD in the child.  

However, the evidence was not very strong, and more studies are needed to arrive at any conclusion because blood folate levels can be related to a number of factors like nutritional intake, cellular folate status, and concentration of other B-vitamins. 

So, can folic acid increase the risk of ASD in the baby? Yes, it might, but only in extreme cases. There could be a risk in case of high dosage of supplementation particularly towards the later stages of pregnancy[7] (last 6 months).  

The new finding stresses the importance of proper dosing of the supplement. Taking a high dose of folate without the recommendation of your OB-GYN during the second and third trimester of pregnancy might increase the risk of autism in the baby.  

Benefits of prenatal vitamins

Prenatal vitamins are specifically formulated to provide a women’s body all the necessary vitamins and minerals needed for a healthy pregnancy. Even if you are on a healthy diet, your body might not get all the vitamins and minerals in the amounts it needs during pregnancy from the diet only, which can increase the risk of miscarriage and defects in the infant. 

Prenatal vitamins should contain a recommended combination of different vitamins and minerals in particular amounts. Folic acid, Calcium, Vitamin D, Iodine, and Iron are the primary vitamins and minerals suggested for supplementation before and during pregnancy. Other B vitamins, Vitamin C, Vitamin E, and Zinc should also be supplemented in trace amounts.  

Folic acid     

Neural tube defects develop early in pregnancy. Folic acid taken before conception and during the first 12 weeks of pregnancy, has been found to reduce the risk of NTDs. Neural tube defects are major birth defects that affect the baby’s brain and spine. The brain development of the fetus occurs early in pregnancy and a deficiency of folic acid during this period might have a role to play. 

400 micrograms of folic acid daily[8] is the recommended dose for women expecting pregnancy and in the early stage of pregnancy. Along with the supplement, you can also take folate-rich foods like nuts, beans, chickpeas, green leafy vegetables, and other folic acid fortified foods.    

Calcium and Vitamin D 

Calcium is essential for the development of the skeletal system of the baby and if the mother is calcium deficient, it might lead to losing bone density for the mother. Vitamin D ensures proper absorption of calcium in the body. 

Including 300mg or more of calcium and 400 IU of vitamin D[9] in daily supplementation is suggested to ensure a healthy pregnancy. Exposure to sunlight can help your body make more vitamin D. Calcium is present in its natural form in dairy, green leafy vegetables, soymilk, eggs, etc. 


Iron is a vital mineral that helps the body to make red blood cells and carry oxygen. If Iron deficiency in the mother can lead to a range of pregnancy complications like low birth weight or infant death. You should try to take more than 45mg of iron[10] every day during pregnancy and breastfeeding. Seafood, dark green leafy vegetables, beans, dry fruits, raisins, and apricots are rich sources of iron in daily diet.  


Iodine plays an important role in the proper functioning of the thyroid gland. The hormone secreted from the thyroid plays a critical role in the neurodevelopment of the fetus and infant. Iodine deficiency in the mother can lead to mental disability and stunted growth of the baby. Iodine deficiency can also lead to miscarriage. 150 micrograms of iodine[11] daily are recommended for pregnant women.    

Reasons of Autism 

ASD is a neurobiological disorder influenced by both genetic and environmental factors[12] that affect the developing brain of the fetus. There are several pre, peri, and postnatal factors[13] that result in an elevated relative risk of ASD in the offspring. 

Maternal and paternal age of 35 or more, gestational hypertension, gestational diabetes, gestational age of 36 weeks or less, fetal distress, postpartum hemorrhage, exposure to cigarette smoke are some of the factors that have been associated with an elevated risk of ASD. Interestingly, a male child has a higher risk of autism compared to a female child.  

It is important to keep in mind that different factors influence the neural development of the fetus and any one factor might not be responsible for the occurrence of the condition. These are risk factors for the development of ASD, but their existence does not confirm the development of the condition in the child.        


According to doctors, folic acid is good for pregnant women and it should be taken in the right dosage not only during early pregnancy but also before pregnancy to reduce the risk of ASD in the offspring. 

Nevertheless, not taking folic acid before or during pregnancy is not a cause of autism in any way. Consumption of folic acid in high dosage in the later stages of pregnancy might have a negative impact on the neural development of the child.  

Prenatal vitamins when taken in the right dosage with a proper diet helps to ensure that there is no vitamin or mineral deficiency in the body of the mother which can hinder the neural or physical development of the fetus or lead to a miscarriage. It also helps to ensure a better physical and psychological health of the mother which is essential for a healthy pregnancy.  

+ 13 sources

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Written by:

Ananya Lahiri

Medically reviewed by:

Ananya Lahiri holds a Bachelor's degree in Life Sciences and a Master's degree in Bioinformatics. She is also the published author of several Health & Wellness blogs, guides, and e-books. With years of experience in the education and e-learning industry, she is keen on sharing information that can help people in making informed choices. Ananya is an avid dog lover with a specific interest in Huskies and GSDs. She is also a certified translator and holds a certificate in digital marketing. Apart from Health and Medical, Ananya also enjoys writing on tech, fashion, and beauty niches. She has crafted study materials for Cosmetology & Nursing courses.

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