A new study, published in JAMA Psychiatry1, has found that women who took vitamins and folic acid either before or during pregnancy were significantly less likely to have a child who went on to develop autism spectrum disorder.
The study followed 45,300 Israeli children (of which around half were girls) born in 2003-2007 and checked for a diagnosis of autism up until January 2015. During this time, 572 (1.3 per cent) children received a diagnosis of autism.
Commenting on the study, dietitian, Dr Carrie Ruxton from the Health and Food Supplements Information Service said: “The results showed a 61 per cent reduced risk of autism when mothers had taken either a multivitamin and/or folic acid supplement prior to becoming pregnant. It was also found that mothers who took these vitamin supplements during pregnancy were 73 per cent less likely to have a child who went on to be diagnosed as autistic.
“While this is an observational study and we need to be cautious, it is an important finding which contributes to our body of knowledge on factors linked with autism.
“Around 75% per cent of women of childbearing age in the UK have an inadequate folate status putting their children at risk of neural tube disorders, such as spina bifida2. Only a quarter of women take the recommended folic acid supplements before conception and in the first trimester of pregnancy3. It is possible, given these new findings, that a lack of key nutrients may also be an issue for autism risk”.
“According to autism charities, over 695,000 people in the UK may be autistic, with a prevalence rate of 1.1 per cent in children4. Taking a daily multivitamin is a useful way of ensuring that women have the nutrients they require. If planning a pregnancy, a daily folic acid supplement of 400 micrograms should be added to this”.
 Levin, SZ et al Are Vitamin Supplements Used Before or During Pregnancy Associated with Risk of Autism Spectrum Disorder?http://jamanetwork.com/journals/jamapsychiatry/fullarticle/10.1001/jamapsychiatry.2017.4050
 Bates B et al. (2015) NDNS Supplementary report: blood folate results for the UK as a whole, Scotland, Northern Ireland (years 1 to 4 combined) and Wales (years 2 to 5 combined). London.
 SACN (2017) Folic acid: updated recommendationswww.gov.uk/government/publications/folic-acid-updated-sacn-recommendations