Pregnant women with low vitamin D levels are more likely to have children with autism traits by the age of six, according to a recent study published in a peer-reviewed scientific journal.

Exploring the link between vitamin D deficiency in pregnancy and autism traits, John McGrath, a professor from the University of Queensland's Queensland Brain Institute, together with his co-researchers, examined 4,229 blood samples from pregnant women and their children, and found those who were deficient in vitamin D had "significantly higher" scores on autism scales than those who had adequate vitamin D levels.

"We speculate that prenatal vitamin D supplementation may reduce the incidence of autism spectrum disorders," said the study, entitled "Gestational Vitamin D Deficiency and Autism-related Traits: the Generation R Study." The study showed that low vitamin D levels may disrupt brain development.

"We should prevent serious mental disorders like autism by making sure women have optimal vitamin D during pregnancy," the study said.

The study may also have important implications from a public health perspective. "It is feasible that a safe, cheap, and publicly accessible vitamin D supplement in at-risk groups may reduce the prevalence of this risk factor," the study suggested.

The association between low vitamin D levels and autism is strongest at mid-gestation and at birth, the study showed.

The blood samples were taken from those closely monitored as part of the long-term "Generation R" study in Rotterdam, the Netherlands.

The study was funded by the National Health and Medical Research Council, and was first published online on Nov. 29, in the journal named Molecular Psychiatry.

Vitamin D can be obtained from exposure to sunlight, and it can also be found in some fruits and vegetables.

Autism, or autism spectrum disorder, is a lifelong neurodevelopmental disorder characterized by impaired social interaction, verbal and non-verbal communication, and restricted and repetitive behavior.