Eating Fish with Mercury During Pregnancy Linked to Autism

Mercury's influence on autistic children has become more and more evident. In this article, we'll show you what the latest research says in respect to this matter.
Eating Fish with Mercury During Pregnancy Linked to Autism
Maricela Jiménez López

Written and verified by the doctor Maricela Jiménez López.

Last update: 12 May, 2022

After decades of research, the question as to why so many children have autism continues to go unanswered. This is because there is not just one single factor.

What is autism?

Autism, also known as ASD (Autism Spectrum Disorder),  is a neuro-biological developmental disorder that starts during the first three years of life and lasts one’s entire lifetime.

Overall, there are two fundamental symptoms that are associated with autism:

  • Persistent deficiencies in communication and social interaction.
  • Restrictive and repetitive patterns of behavior, interests and activities.
Autism does not have a known origin.

Some signs that may be indicative of  ASD in children are:

  • Lack of communication with other children in Kindergarten or grade school.
  • Absence of symbolic play (taking care of dolls, playing house, playing with cars as if they were real, etc.).
  • Little eye contact is made and they don’t notice a change in the other person’s face when they are both looking at something strange. In addition, children with autism don’t make the normal social smile when interacting with others.
  • Their language, if they speak, is literal (thus, they don’t understand jokes, sarcasm, double meanings or metaphors).

Overall, many scientists tend to agree that genetics are a factor in having this condition.

What is the relationship between autism and mercury?

Studies show that many metals such as mercury can affect autism if women consume them during pregnancy.

Mercury is a chemical element with the symbol Hg and atomic number 80. In ancient literature, it was commonly referred to as liquid silver or quicksilver. With a silver-like appearance, it is a heavy metal that belongs to the D block of the periodic table. Mercury is the only metallic element that is a liquid under standard laboratory conditions.

In a study done by the University of Bristol, scientists analyzed data on more than four thousand pregnancies. Then, they discovered a relationship between the level of mercury in the mother’s blood and the appearance of ASD in children under 11 years of age. Thus, they believe they found a correlation between the onset of autism in children and the intake of mercury-contaminated fish in pregnant women.

Conclusions of the Study

This study concentrated on newborn children in the former county of Avon, England, in 1991 and 1992. Currently, it is run by George Davey Smith. Overall, the study included 15,247 pregnant women with estimated delivery dates between April 1991 and December 1992. Since then, the parents, the siblings and the children of the participants have also been a part of the study.


Overall, the study indicates that 4,484 women had high levels of mercury in their blood. These women stated that fish was their main source of meat during their pregnancy. Of that total, 177 pregnant women had an autistic child. Of the newborns, only 45 had mercury in their blood.

However, it’s important to note that many of the other children belonged to lower socioeconomic classes. Thus, their mothers did not eat a lot of fish during their pregnancy.Because of that, they had less exposure to this risk factor.

In addition, the researchers said that the condition was more common in women who had a high level of mercury in their blood during the first half of their pregnancy.

Therefore, the study concluded that a high consumption of fish during the first half of pregnancy increases the chances that the future child will suffer from Autism Spectrum Disorder.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Kakita A, Inenaga C, Sakamoto M, et al. Neuronal migration disturbance and consequent cytoarchitecture in the cerebral cortex following transplacental administration of methylmercury. Acta Neuropathol (Berl) 2002;104:409–417.
  • Harada M. Minamata disease: methylmercury poisoning in Japan caused by environmental pollution. Crit Rev Toxicol. 1995;25:1–24
  • Amin-Zaki L, Elhassani S, Majeed MA, et al. Intra-uterine methylmercury poisoning in Iraq. 1974;54:587–595.
  • Kraepiel AM, Keller K, Chin HB, et al. Sources and variations of mercury in tuna. Environ Sci Technol. 2003;37:5551–5558.
  • Grandjean P, Weihe P, White RF, et al. Cognitive deficit in 7-year-old children with prenatal exposure to methylmercury. Neurotoxicol Teratol. 1997;19:417–428.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.