Mercury from eating seafood affects fertility and pregnancy

What is mercury?

Mercury is a heavy metal element that occurs naturally in the environment. Mercury is also created and released into the air through industrial pollution. From the air, mercury can enter the water in streams and oceans and be converted to methylmercury. As fish feed in the contaminated waters, the levels of methylmercury build up in their muscles. As a general rule, the bigger or older the fish, the more mercury will have build up in them. also, certain types of fish seem to accumulate mercury to a greater extent than other types.

Why is mercury a problem?

Methylmercury is the form of mercury that can potentially be harmful to women attempting pregnancy, unborn babies and small children. If a person regularly eats types of fish that are high in methylmercury, it can accumulate in their blood over time. Babies and small children are more sensitive to the effects of mercury and are therefore at potentially greater risk. since it takes the body many years to get rid of mercury, women may have high levels even before they attempt pregnancy.

Mercury Levels in Seafood and Fertility

As stated above, mercury contamination has been found in many different types of seafood. Most women are now aware of the relationship between eating contaminated seafood while pregnant and the risk of giving birth to babies with birth defects and neurologic impairment. Recent studies have also demonstrated however that mercury consumption may also be related to infertility and miscarriage.

One study found that a group of infertile men and women had higher blood levels of mercury than a similar group of men and women with normal fertility. Men who had an abnormal semen analysis and women with otherwise unexplained infertility also had higher levels of mercury. The higher levels corresponded to increased consumption of seafood.

We therefore advise all patients who are attempting to conceive to try to reduce their consumption of mercury contaminated seafood. The graphic below from the U.S. Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) separates different types of fish based on levels of mercury found in each. You can use this as a guide but keep in mind that these categories are subject to change.

What about fish sticks and fast food fish sandwiches?

According to the FDA/ EPA fish sticks and fast food fish sandwiches are commonly made from fish that are low in mercury. Safety tips

  • Do not eat any of the fish that contain high levels of mercury in the graphic below
  • Eat 2 to 3 servings of fish a week from the “Best Choices” list OR 1 serving from the “Good Choices” list.
  • Eat a variety of fish.
  • Serve 1 to 2 servings of fish a week to children, starting at age 2.
  • If you eat fish caught by family or friends, check for fish advisories.
  • If there is no advisory, eat only one serving and no other fish that week.
Mercury levels in seafood

What is a serving?