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Limiting Seafood Long Before Pregnancy


by Cindy Bailey of the Fertile Kitchen®, June 23, 2010

You probably already know that you need to avoid seafood during pregnancy, due to the harmful effects its mercury levels can have on a growing fetus. But did you know it’s important to avoid seafood while trying to conceive too?

Here’s why. Mercury from industrial production gets into our water, taking the form of methylmercury, which then gets into our seafood. Bigger fish accumulate higher levels, as they tend to eat the smaller fish. We then consume the fish, scallops, sushi, crab and so on.
Once in the human body, mercury acts as a neurotoxin, interfering with the brain and nervous system, which is not good for the health, so it can’t be good for fertility either! But worse, once mercury (or methylmercury) gets into our bodies, it stays a while, accumulating in our blood. Our body naturally gets rid of it, but it can take time —up to six months or more!

In that time, if you get pregnant and still have harmful levels in your body, the methylmercury passes through your blood to the developing fetus, and it can cause impaired neurological development. According to an article on the EPA’s website states:

    “Methylmercury exposure in the womb, which can result from a mother's consumption of fish and shellfish that contain methylmercury, can adversely affect a baby's growing brain and nervous system. Impacts on cognitive thinking, memory, attention, language, and fine motor and visual spatial skills have been seen in children exposed to methylmercury in the womb.”

So, it’s important when trying for a baby that you start to limit your seafood as soon as possible. This means eliminating fish with the highest levels of mercury, which, according to the FDA, include swordfish, tilefish, king mackerel and shark. For other seafood, limit yourself to low-mercury options and consume them only twice a week at most.

For a guide on which seafood has the lowest mercury levels, see this FDA (Food and Drug Administration) chart. Also, I found this handy Mercury Calculator put out by the NRDC (Natural Resources Defense Council).

Before you panic, however, know that in a July 2005 report, the Centers for Disease Control and Prevention (CDC) found that one in 17 (that’s 6%) women of childbearing age have 5.8 micrograms per liter or more of mercury in their blood, which is a level that could pose risk to a developing fetus.

Six percent is not a lot. However, if you’re someone who loves seafood or sushi and/or are worried about your mercury levels, I encourage you to get your blood checked by your doctor or naturopath. And save the sushi for special occasions, post-baby.

Here’s some excellent additional information:

You can read more about fertility risks or eating for fertility in my previous blogs.

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Comments (1)

An excellent tool to gauge how much potential mercury is in the fish you are eating is the free on-line calculator found at

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