If you've ever been pregnant, you will recall that one of the first things your health care provider will advise you on is what to eat and not eat while pregnant. Fruits and vegetables? Yes. Soft cheeses and hot dogs? No. Fish? Well, that's a maybe.  


The consumption of fish is tricky for pregnant women because in and of itself, fish is a healthy food to eat, packed with vitamins, lean protein, and the right fats and oils to help a baby grow. But depending on the type of fish selected, it may be unhealthy for pregnant women to eat due to its likely mercury content.  


A new study published this week in the Archives of Pediatrics & Adolescent Medicine confirms this conflicting advice.  Researchers found that eating at least two servings of fish per week was linked to about a 60 percent lower risk of kids developing certain ADHD-like symptoms. However, the study also found that pregnant women who had higher mercury levels — likely from eating certain kinds of fish — had a higher risk of having babies who would develop ADHD symptoms, such as hyperactivity, impulsiveness and inattentiveness.


Researchers evaluated 600 mothers and children from New Bedford, Mass., and found that children who are exposed to higher levels of mercury in the womb are more likely to exhibit attention problems, hyperactivity and other ADHD symptoms when they're 8 years old. Prenatal mercury exposure was measured by analyzing samples of the mothers' hair shortly after birth.  


So what's a pregnant woman to do? According to the Environmental Protection Agency, swordfish, shark and king mackerel are among the fish high in mercury while shrimp, canned light tuna, salmon and catfish have the lowest amounts. Talk to your health care provider if you are concerned about the amount of mercury you may be consuming while pregnant.


Related mercury story on MNN: How much mercury is in the fish we eat?


Prenatal mercury exposure linked to ADHD
New study advises women to eat fish while pregnant, but hold the mercury. Researchers evaluated 600 mothers and children and found that children who are exposed