Researchers compared expectant mothers who take multivitamins with those who don’t and found significant differences in the autism rates of their children, according to the new research published in the British Medical Journal (BMJ).

The researchers stressed that their findings cannot establish a cause-and-effect relationship between autism and vitamin deficiency during pregnancy, but said the study suggests a possible association that warrants further investigation.

ASD includes a range of conditions, including Asperger syndrome, that affect social interaction, communication, and behavior. About one in every 100 people has ASD.

Past research indicates ASD may develop in the womb and that a mother’s diet during pregnancy could have an influence.

For the new study, an international research team sought to determine whether nutrient supplementation during pregnancy can reduce the risk of ASD.

They tracked 273,107 mother-child pairs living in Stockholm, Sweden, over an 11-year period ending in 2007.

Researchers assessed the women’s reported use of folic acid, iron, and multivitamin supplements in early pregnancy and cases of child ASD were identified from national registers.

The findings showed that multivitamin use, with or without additional iron and/or folic acid, was associated with a lower likelihood of child ASD.

“Together, the … analyses appear to point toward a potential inverse association between multivitamin use with ASD with intellectual disability,” the authors concluded.

They added that the findings “raise questions that warrant investigation” and call for verification in randomized studies “before recommending a change to current practice.”