Is Eating Fish Safe For Your Fertility?


Fish consumption is associated with many different types of health benefits. It is naturally high in omega-3 fatty acids, and also high in other nutrients and vitamins such as Vitamin D, B-12, and iron. Studies suggest eating fish can protect your heart against cardiovascular disease, boost your brain function, protect your vision, and lift your mood. And for mamas-to-be, this nutrient dense food used to be something routinely recommended as the high levels of DHA contained in fish is so important for a baby’s developing brain and nervous system.

Unfortunately, an increasing number of research studies have shown just how much fish can absorb the toxicity in our now polluted waters. They absorb things like mercury, PCBs, and microplastics, among other ocean pollutants.

In fact, because of these potential adverse effects, the Environmental Protection Agency and the FDA have had targeted campaigns to help educate OB/gyn’s, primary care doctors, pediatricians, gynecologists, nurse practitioners, nurses, and physician’s assistants on food safety both for women trying to conceive and pregnant women on the possible dangers of fish consumption. But are these campaigns and fish eating guidelines enough to prevent maternal transmission of these toxins? Read on for more on this.


In a 2013 study from Food and Chemical Toxicology, women of child bearing age who ate fish were studied as to the effects of not only the beneficial DHA, but also the effects of harmful mercury. This study concluded that the negative effects of mercury ingestion outweighed the beneficial effects of DHA on a child’s neurodevelopment. 

Mercury levels can stick around in the body for much longer than most people suspect. In one 2012 study looking at the time it took for mercury to clear from the body, researchers fed tuna twice a week to participants to drive up their methylmercury levels for three months. Then, they had participants stop eating the tuna and watched how quickly levels of mercury subsided. What they found was that the half life for clearing mercury from the blood took about three months. This means that it takes about three months for your body to get rid of half the amount of mercury from fish consumption once you stop eating it. And then it took about a year for most bodies to clear about 99% of the mercury from their blood. 

What about mercury in the brain? If mercury enters the brain, some estimates (which seem to be consistent with autopsy findings) point to a possible range from months to decades for mercury to be cleared. And for persistent organic pollutants, it seems it can also take years to clear from the body.

Persistent Organic Pollutants (POPs)

Mercury isn’t the only toxin to be wary of if you are trying to conceive. Industrial pollutants in our seawater is also a big concern. Certain dioxins (highly toxic chemicals), PCBs (certain industrial chemicals which have been banned but still found residually in our environment) and DDT (an insecticide which has been banned but still found residually in our environment) metabolites in fish can take up to ten years for half of the amounts ingested to be eliminated from our bodies. Further, for our bodies to rid 99% of these pollutants, it could take over 100 years. 

Persistent organic pollutants (POPs), such as these, can have profound effects on our health and fertility.  Exposures to these pollutants have been found to increase the length of time it takes for couples to become pregnant and disrupt reproductive hormones.

For women who do become pregnant, these chemicals have a widespread effect on their babies. According to one study, babies whose mothers ate large amounts of PCB contaminated fish had lower birth rates, smaller head circumferences, and shorter attention spans than babies whose mothers did not eat fish. This study followed the kids for many years and found the effects continued with deficits in general intellectual functioning, memory, and attention span.

In another study on a particular POP called PCB-153, researchers found no decrease in the chemical after women stopped eating fish until they hit the 5 year mark of fish elimination. This research suggests for women who are trying to get pregnant, it is advisable to eliminate fish consumption for at least 5 years to avoid maternal transmission of these chemicals. 

The FDA currently recommends that pregnant women and children eat only 2-3 servings of the lower mercury containing fish per week. However, this recommendation does not take into consideration these other toxic pollutants. In fact, pollutants with long half lives will not necessarily be reduced with the current advisories for maternal transmission. 


Besides heavy metals like mercury and POPs, there is another rising concern with eating fish - microplastics. Microplastics are small pieces of plastic less than .2 inches in diameter. They can be created for products, like some skincare exfoliants for example, or broken down from larger pieces of plastic. Due to our increased reliance on plastic products, plastics are landing in our oceans, rivers, and lakes at astonishing rates. In fact, almost 9 tons of plastic waste enter our oceans every year. With this, fish and other marine life end up consuming a fair amount of microplastics. 

Unfortunately, when we consume fish (and especially shellfish which have highest accumulation of microplastics), we consume these microplastics. MIcroplastics can be found in the gut and in the flesh of the fish. For example, with one serving of mussels you consume about 90 plastic particles and with one serving of oysters you consume about 50. And, another study found that microplastic intake from eating flathead, grouper, shrimp, barracuda, and scad could be in the hundreds per 300gm serving of these fish. However, canned sardines may contain less microplastics as they have been gutted. One study looking at multiple brands from multiple companies of canned sardines found only 1 in 5 cans contaminated with microplastics, most likely due to processing out the guts.

More studies need to be done on the effects that microplastics have on our health, so we don’t clearly know yet what these effects may have on our general health and reproduction. However, we do know that microplastics can accumulate in our liver, kidneys, and intestines. We also know that both pthalates (a chemical used to make plastic pliable) and bisphenol-A (BPA) from other sources clearly interfere with our hormones and reproduction. 

How About Fish Oil Supplements?

A 2013 study looked at the level of PCBs (a group of over 200 industrial chemicals which have since been banned) in children’s fish oil supplements. What they found was that every one of the supplements had PCBs contained in them. Further, the levels of PCBs were the same in the products which used a molecular distillation process and in the products which used a smaller fish (like anchovies, so further down on the food chain) and those fish like tuna who are higher up on the food chain. 

In fact, the Environmental Justice Foundation tested fish oil supplements found in retail stores to see if they contained PCBs. They tested these supplements to determine if they were violating California law which stipulates that the public should not be exposed to more than 90 nanograms of PCBs daily without a written warning on the bottle. What they found was that some of them had 70 times the level of PCBs than others. The fish oil supplements tested and found to be in violation included bottles which had claims such as "Screened for PCBs" or "Treated to Remove PCBs."

If you do take fish oil supplements, these are the things to look for in a supplement company:

  • Source fish lower on the food chain. Sourcing fish like anchovies or sardines for fish oil ensures less accumulation of mercury, PCBs, and other toxins.

  • Uses molecular or flash distillation process. This is a low heat process where mercury and other contaminants are mostly removed from the fish oil.

  • Third-party tested. Since the supplement industry is largely unregulated, it’s important that you buy from a company that does independent third-party testing for heavy metals and other contaminants.

  • Uses sustainable fishing methods. Choose a company that is committed to sourcing fish which are flourishing.

Are There Other Ways To Get Those Beneficial Omega-3’s?

Is it even important for women trying to fall pregnant to consume omega-3’s? Yes! Mothers are given DHA supplements had children with significantly better vision at 2 months, significantly better problem solving at 9 months, and significantly smarter at 4 years old. So, we know that for women who are trying to conceive, pregnant, and breastfeeding, DHA consumption is extremely important.

There are multiple other ways of getting in those beneficial omega-3’s without being exposed to high levels of mercury, PCBs, microplastics and other pollutants. 

There are three main types of omega-3’s: alpha-linolenic acid (ALA), DHA, and EPA.

Many foods have a fair amount of these omega-3’s built right in. These include avocados, flaxseeds, chia seeds, walnuts, pumpkin seeds, and hemp seeds. In fact, spinach and Brussel sprouts even have a fair amount of omega-3’s built into them. These foods generally contain the omega-3 ALA, which is then converted to DHA and EPA in the body. However, only small amounts of ALA are converted. So, for optimal fertility, these food sources may not provide enough omega-3’s and an additional supplement of DHA is recommended.

The other way to get in those beneficial amounts of DHA without consuming fish is by going to the original source where the fish get their omega-3’s from, algae. Algae oil is a sustainable way to get omega-3’s without the added ingestion the toxins. For women who are currently trying to conceive, I recommend 500-600mg of DHA daily. The algae-based brand I recommend to my clients is called Ovega-3.


Because of the issues with mercury, microplastics, and other pollutants found in fish, it may be worth it to avoid most or all fish consumption if you are currently trying to conceive (or planning on getting pregnant in the future).

To avoid the effects of mercury ingestion, eat the types lowest in mercury the majority of the time. These include salmon, anchovies, haddock, sardines, trout, and cod. To avoid intake of microplastics, eating canned fish which have been gutted may reduce your intake of these chemicals. Lastly, to avoid persistent organic pollutants (POPs), eating fish lower on the food chain will reduce toxic accumulation.

There is much more to this issue, including the global mislabeling rates of seafood (about 30%!), eating farmed vs. wild caught fish, by-catch issues (fisherman in the U.S. throw away approximately 20% of what is caught due to size or poor quality), and the effects of fishing on larger marine mammal population (with shrimp trawling, huge nets are used which catch tens of thousands of sea turtles, for example, who are then discarded as waste). There is certainly much to think about and take into consideration when you decide to eat your next seafood meal.

Are you a woman trying to naturally boost your fertility and looking for help? Book a FREE 30-minute Fertility Breakthrough call with me here.  I’d love to help you get started!


Laurie Terzo