Consumer Reports warns pregnant women should avoid tuna 'altogether' due to mercury risks

Consumer Reports is warning pregnant women that they should avoid tuna altogether due to the potential for unpredictably high levels of mercury in individual cans of the fish. 

The organization said in a report this week that "while canned tuna, especially light varieties, has relatively low average levels of mercury, individual cans can sometimes have much higher levels."

"From can to can, mercury levels can spike in unpredictable ways that might jeopardize the health of a fetus,” CR Food Safety Director James Rogers said in the report. 

Mercury, the organization pointed out, is "present to some degree" in all fish, though it is found in higher concentrations in larger fish.

Studies from CR found that albacore tuna "has much more mercury than light or skipjack tuna," in large par because "albacore is larger and lives longer than the tunas that make up the light tuna or skipjack tunas."