• Jasmine Blake Hollywood, MS, HHP

Seafood and Pregnancy

Controversies of Eating Seafood While Pregnant

Seafood and pregnancy remain to be a significant controversial subject for women. The basis for this controversy lies between Mercury being the neurotoxin that interferes with fetal brain development and consuming Omega 3 fatty acids for optimal health. [4]. Women fear the safety of their unborn child because they think they will get mercury intoxication from eating fish. When making this choice, they also deprive their unborn child of essential nutrients.

Essential Nutrients

Essential nutrients, such as Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) are considered fatty acids. Fatty acids are critical for the neural development of the fetus, brain development, and the development of the retina.[1;2;3]. Most women who consume little to no fish do it because of taste preference, fear of harming the fetus, or because they don't know to eat it. The Food and Drug Administration (FDA) recommends that pregnant women should consume fish daily to acquire their daily fatty acid requirements. Eating fish is preferred by the government because fish contain both EPA and DHA. However, when women are choosing to avoid fish because of rumor, the choice ultimately deprives the fetus of these necessary nutrients doing more harm than good. 

Eating Fish is Necessary

When women avoid foods that provide proper nutrition, they deprive their bodies of essential nutrients. This choice can lead to abnormal development of the brain and neural system, the child being born prematurely, or the child being born at low birth weight. If the nervous system or brain doesn't develop correctly, then the fetus may be born with complications. Complications could include mental illness, motor skills development, verbal skills development, phospholipid (fats) imbalance in the retina, abnormal nervous system development. The risks for poor nutrition can be just as severe as the risks of getting Mercury intoxication.

Mercury Intoxication

Mercury intoxication happens when eating longer-lived, larger fish. To achieve the lowest intake of Mercury, it is suggested to eat shorter-lived smaller fish. This suggestion is based on researched evidence that longer-lived, larger fish contain higher amounts of Mercury, than shorter-lived, smaller fish. [5]. Also, shorter-lived smaller fish do contain both Omega 3 FA and Selenium the same as longer-lived, larger fish. [4]. In addition, Mercury intoxication is even worse when it is turned to mono-methyl-mercury.

Bacteria play a part in Mono-Methyl-Mercury

There are bacteria everywhere, even in the ocean. Certain bacteria can turn Mercury into it other form mono-methyl-mercury. Smaller fish eat the bacteria that turn Mercury into mono-methyl-mercury. Longer-lived larger fish eat the shorter-lived, smaller fish. Because of this, The Mercury builds up in longer-lived larger fish over time. [4]. Also, mono-methyl-mercury can cross over the placenta membrane into the fetal capillaries. As well, it can pass through the blood-brain-barrier. Eventually, Mercury builds up in the fetus. In turn, this causes disproportionate neural development. Furthermore, if eating fish that have high Selenium content, it is said that the Selenium can decrease the effects of momo-methyl-mercury, and protect against toxicity. [4].


Women should eat fish to get the essential nutrients that the fetus needs in order to promote healthy development. Small amounts of Mercury can get into the body even if a person doesn't consume fish. Therefore, eating fish shouldn't be based on the premise that there is Mercury in it. Although, women should avoid larger species that contain higher amounts of Mercury due to the high rates of toxicity Mercury causes. Women should make the best choices for their unborn children and not for themselves. Viewing the chart below for recommended daily allowances of fish can help a pregnant understand Mercury levels.


  1. Bloomingdale, A., Guthrie, L. B., Price, S., Wright, R. O., Platek, D., Haines, J., & Oken, E. (2010). A qualitative study of fish consumption during pregnancy. The American Journal of  Clinical Nutrition, 92(5), 1234–1240. doi:10.3945/ajcn.2010.30070. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131842/Links to an external site.

  2. Coletta, J. M., Bell, S. J., & Roman, A. S. (2010). Omega-3 fatty acids and pregnancy. Reviews in Obstetrics & Gynecology, 3(4), 163–171. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3046737/Links to an external site.

  3. Greenberg, J. A., Bell, S. J., & Ausdal, W. V. (2008). Omega-3 fatty acid supplementation during pregnancy. Reviews in Obstetrics & Gynecology, 1(4), 162–169. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2621042/Links to an external site

  4. Mahan, L. K. & Raymond, J. L. (2017). Krause's food & the nutrition care process (14th Ed.). St. Louis, MO: Elsevier

  5. Wooltorton E. (2002). Facts on mercury and fish consumption. Canadian Medical Association Journal, 167(8), 897. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC128404/Links to an external site.

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