Consuming Fish with Traces of Mercury During Pregnancy Does not Amplify Risk of Autism in Children

A new study reveals that, exposure to mercury during pregnancy through fish consumption does not increase risks of autism spectrum disorder (ASD), a developmental disorder found among children.

Innumerable studies in the past have shown a strong link between autism and early exposure to heavy metals like lead and mercury.

Though mercury is naturally present in the environment, industries play a major role in increasing its level in the air. Mercury in the air is gathered in oceans and streams. It is later transformed into methylmercury in water and is absorbed by fish.

As most of the shell fish and some other species contain traces of mercury, pregnant women are always advised to completely avoid eating sharks, swordfish, king mackerel and tilefish. They are also urged to limit their intake of mercury-containing fish diet to two average meals.

However, the current study published in Epidemiology didn't find any link between exposure to mercury through maternal fish intake and autism.  

The study was conducted in the Republic of Seychelles, a 115-island country in the Indian Ocean, where fish is a staple diet. According to the background information provided in the study, the fish intake among local residents is 10 times higher than in the U.S. and Europe.

The current study included 1,784 children and their mothers, registered in The Seychelles Child Development Study that was conducted around the mid-1980, to analyze the negative impact of early exposure to mercury through fish consumption.

To determine the baby's exposure to mercury, researchers tested hair samples of pregnant women.  Prevalence of autism among the children was determined through questionnaires on language skills, social communication and repetitive behavior, answered by parents (Social Communication Questionnaire) and teachers (Social Responsiveness Scale).

Researchers compared test scores of the children with mercury levels of mothers; however, they couldn't find any association between the two.

"This study shows no evidence of a correlation between low level mercury exposure and autism spectrum-like behaviors among children whose mothers ate, on average, up to 12 meals of fish each week during pregnancy," lead author of the study Dr. Edwin van Wijngaarden, an associate professor in the University of Rochester Medical Center's (URMC) Department of Public Health Sciences, said in a news release.

Though fish intake during pregnancy has long been a source of concern, many previous studies have shown eating fish during pregnancy boosts baby's brain development as it is a rich source of omega-3 fatty acids. Apart from that, studies have also shown that eating fish during pregnancy lowered risks of ADHD in children and the selenium in fish eliminated the risks posed by mercury.