"Evidence not yet sufficient to change practice but findings warrant further investigation say researchers Taking multivitamins during early pregnancy may be associated with a reduced risk of autism spectrum disorder ASD in children compared with mothers who do not take multivitamins finds a study published in The BMJ today. The researchers stress that their findings cannot establish cause and effect but say they raise questions about a possible association that warrant further investigation. Autism spectrum disorder ASD includes a range of conditions including Asperger syndrome that affect a persons social interaction communication interests and behaviour. Its estimated that about  in every  people in the UK has ASD. More boys are diagnosed with the condition than girls. Research indicates that ASD most likely develops in the womb and that a mothers diet during pregnancy could have an influence. But results from previous studies have been inconsistent suggesting that other unmeasured factors confounding such as a mothers overall health and lifestyle could also play a role. So an international research team set out to assess whether nutrient supplementation during pregnancy is associated with reduced risk of ASD with and without intellectual disability. They applied three analytical methods to a sample of  motherchild pairs living in Stockholm Sweden. The sample was restricted to children who were  to  years of age by December   and were born between  and . Women reported their use of folic acid iron and multivitamin supplements at their first antenatal visit and cases of child ASD were identified from national registers. After adjusting for several potentially influencing factors in both mothers and children the researchers found that multivitamin use with or without additional iron andor folic acid was associated with a lower likelihood of child ASD with intellectual disability relative to mothers who did not use folic acid iron and multivitamins. There was no consistent evidence that either iron or folic acid use were associated with a reduced risk of ASD. The results of the various analyses seemed to be consistent with each other say the authors suggesting that the association between multivitamins and ASD might not be fully explained by confounding. They point to several study limitations such as the potential for confounding and difficulty assessing type timing and dose of supplements. However strengths included the relatively large populationbased sample size and the advanced analytical methods used to gauge the robustness of findings. Together the three analyses appear to point toward a potential inverse association between multivitamin use with ASD with intellectual disability say the authors. Given the current understanding and strength of evidence supporting the importance of nutritional supplementation during pregnancy it is impossible to imagine that these results on their own should change current practice they write. However they say these findings raise questions that warrant investigation and call for verification in randomised studies before recommending a change to current practice. Ends Notes to Editors Research Antenatal nutritional supplementation and autism spectrum disorders in the Stockholm youth cohort population based cohort study https Journal The BMJ"