Consumer advocates are urging the government to advise women to limit tuna consumption because of mercury levels.
The FDA says it has no plans to explicitly warn women when it issues new consumer advice on mercury in fish this spring.
According to Doctor Richard Raymond of the Nebraska Health and Human Services, mercury contained in fish enters the mother’s bloodstream. During the pregnancy the blood can circulate directly into the babies brain, because there is no blood barrier.
He says the metal can cause problems with regular cognitive development during the fetal stages such as decreased coordination.
In 2002, the FDA's own advisers recommended saying that two 6-ounce cans of tuna a week is fine if that's the only fish pregnant women eat; a single can is OK if they eat other fish, the agency says.
Doctors strongly stress that women who are currently pregnant, who did not know about the warning, do not become alarmed. They say expecting women who have had regular ultrasounds and amneos should experience no problems.