(WJW) — Many people eat canned tuna regularly as a relatively cheap and healthy option, but a recent study suggests that pregnant people would be better off avoiding it completely.

In a study, Consumer Reports found “unpredictable” spikes of mercury levels in cans of popular brand tuna.

After testing 30 samples from five canned tuna brands, Consumer Reports says it found that some individual cans can have significantly higher mercury levels than others, potentially posing a risk during a pregnancy.

“From can to can, mercury levels can spike in unpredictable ways that might jeopardize the health of a fetus,” said James E. Rogers, PhD, director of Food Safety Research and Testing at Consumer Reports.  

According to the FDA, eating seafood is the most common way for Americans to be exposed to mercury, but most seafood doesn’t have levels high enough to negatively affect us.

The FDA says fetuses, infants and young children are more vulnerable to the potential effects of mercury due to their small bodies, metabolism and speedy growth.

Thus, there are set guidelines by the FDA for eating fish while pregnant.

While mercury levels varied, the Consumer Reports study found significantly lower levels among cans of light and skipjack tuna than albacore tuna.

The National Fisheries Institute told Consumer Reports that the mercury levels found in the study were much lower than the FDA limit, saying it is safe to eat.

According to a survey conducted by Consumer Reports back in November, about one-third of Americans eat canned tuna twice a month or more.