Pregnant women may be unknowingly harming their babies if they follow advice to reduce fish intake, according to a new study.

Published in the Lancet by researchers Joseph Hibbeln from the US National Institutes of Health and colleagues from Bristol University, the study results point out that fish is indeed not to be restricted in the diet of pregnant women.

The U.S Government and British Food Standards Agency recommend that expecting mothers should curtail amounts of fish consumption due to high levels of the heavy metal, mercury that is a well-documented contaminant of sea fish.

Fish such as the swordfish, Marlin, Tuna and shark are said to contain very high amounts of mercury due to the polluted waters in which they live.

In 2004, the U.S government and environmental regulators warned of the risks of more than 340 g of fish per week to pregnant women. Another study last year by Harvard University, cautioned against excessive fish intake as pregnant women who ate a lot of sea fish and whale blubber gave birth to children who had irreversible damage to certain brain functions.

Yet, Hibbeln and colleagues say that is just the opposite; restricted fish diet will actually lead to poor fetal brain development.

Hibbeln says that as fish contain high amounts of omega –3- fatty acids and other nutrients, cutting down on the consumption will lead to worse problems.