However, the study notes a lack of association between maternal B12 levels and offspring Asperger’s or pervasive developmental disorder.
“This is the first population-based study examining maternal vitamin B12 levels in prenatal serum in relation to ASD,” the Finnish and American researchers stress, highlighting the significance of the findings for future dietary recommendations during pregnancy.
They highlight the need for further studies to investigate the link further, adding: “The study raises questions on the impact of very extremely elevated levels of maternal vitamin B12 levels on early brain development.”
Autism Spectrum Disorder (ASD) is a group of conditions effecting the ability to socially interact and communicate, whilst restricting further behaviours and activities.
It has been established that autism has a multi-factorial and complex etiology, largely stemming from a combination of genetic and environmental causes. Additional evidence has also suggested the importance of maternal nutrition in the risk of developing ASD.
Such nutrients identified to have an influence include folate, vitamin D, iron, and polyunsaturated fatty acids. The importance of B12 for foetal development is also widely recognised, with optimal levels preventing issues such as neural defects and brain atrophy, due to its vital role in growth and development.
Studies have highlighted associations of vitamin B12 and folate deficiencies with poor foetal neurodevelopment, as well as further cognitive function issues. In addition, a study highlighted the potential risk of high B12 levels and the risk of ASD.
Considering these findings, the researchers conducted the present population-based study to examine this potential link in a Finnish birth cohort-case offspring.
The researchers included 1,558 infants born between 1987 and 2007, who were diagnosed with ASD in 2015. The infants were then matched with a control born on the same date, in the same place, with the same gender.
Maternal vitamin B12 levels were measured during the first and second trimesters of the pregnancy.
It was observed that high B12 levels were associated with an increased risk of the offspring developing autism during childhood.
However, no association was found between the maternal B12 and the prevalence of Asperger’s or pervasive developmental disorder in the offspring.
“We found high levels of maternal vitamin B12 (≥81th percentile) during early pregnancy associated with offspring childhood autism,” the researchers concluded, drawing attention to previous studies reporting similar findings, strengthening the research conducted.
The report highlights the role of B12 in deoxyribonucleic acid methylation, cellular growth, and differentiation, yet notes the lack of understanding of the role of maternal levels in infant brain development.
“If these findings are confirmed in future studies, it would indicate that maternal vitamin B12 has specificity as an etiological factor for a severe form of ASD and high maternal vitamin B12 levels have toxic effects on offspring,” they emphasise, highlighting the importance of further study into the area.
Whilst the study included a large sample, enhancing the validity and reliability of the findings, future research must investigate causality utilising stronger methods of control.
“Maternal Serum Vitamin B12 during Pregnancy and Offspring Autism Spectrum Disorder”
by Andre Sourander, Sanju Silwal, Heljä-Marja Surcel, Susanna Hinkka-Yli-Salomäki, Subina Upadhyaya, Ian W. McKeague, Keely Cheslack-Postava and Alan S. Brown