USA – Excessive intake of folic acid during pregnancy can be harmful to the future baby, according to a study by the Bloomberg School of Public Health at Johns Hopkins in Baltimore (Maryland, USA). The researchers found that if women had a high level of folate – more than four times what is considered normal – may risk of your child developing autism spectrum disorder (ASD).

As explained by one of the main authors of the study, Dr. M. Daniele Fallin, director of the Center Klag Wendy Bloomberg School for Autism and Developmental Disorders, folic acid supplements during pregnancy prevent birth defects in the fetus and are key to proper cellular and neurological development, which exert a protective function for the baby, however, the study results show that an excessive amount of vitamin B12 can also be harmful, so it is necessary levels this micronutrient are adequate.

The study authors studied data from 1,391 mothers and their children included in the Boston Birth Cohort, a population in which predominated people with low economic level. They followed the women from birth for several years, checking the blood folate levels for the first time between the third and tenth day after the birth of the child. One in ten mothers in the study had an excess of folic acid (more than 59 nanomoles, when WHO has established as normal levels to be between 13.5 and 45.3 nanomoles per liter per liter in the first trimester of pregnancy).

Although most participants in the study said they had taken supplements of multivitamins, which included folic acid and vitamin B12 throughout pregnancy, researchers failed to find out why some of them had such high blood levels of these substances but attribute it to taking too many supplements, excessive intake of fortified with folic acid, or even that they might be genetically predisposed to greater absorption of these nutrients. These experts have warned of the need for further research to determine how much folate a pregnant woman should consume in appropriate and safe amount.