Recommendations published in the magazine Consumer Reports this week urge women to avoid eating any canned tuna while pregnant because of uncertainties about the risk of mercury contamination to developing fetuses.

The recommendations are stricter than the federal government's advice issued two years ago. Then, the FDA advised women and young children to limit — but not avoid — consumption of canned tuna because of contamination.

But the magazine's experts say women should avoid the popular item altogether because of FDA data showing that some canned tuna may have higher mercury levels than once thought.

"What we did is take a closer look at the data," says Urvashi Rangan, Ph.D., a toxicologist and a senior scientist at Consumer Reports.

But the Consumer Reports analysis of the FDA's data shows that 6% of cans of light tuna contained at least as much mercury as white tuna, also known as albacore. It wasn't enough to skew the average beyond white tuna, but enough to warrant concern for pregnant women, Rangan says.

"We're not telling you not to eat tuna. But for pregnant women in particular where you are talking about potential fetal exposure - and it's an avoidable risk - we're saying go ahead and take some extra measures to reduce your Hg [mercury] exposure at all costs," she tells WebMD.