One dietary recommendation during pregnancy is to avoid foods with mercury. Mercury is a liquid metal that is a naturally occurring element released by volcanoes and rocks. Much of the mercury that is in bodies of water—and the fish that live in them—comes from air pollution. Exposure to mercury mostly happens in certain types of work, often called “occupational exposure.” Eating fish is the main way that people are exposed to mercury outside of the workplace. Mercury has many negative effects on the body, especially on the brain. The US Environmental Protection Agency and Food and Drug Administration recommend that pregnant women should limit their fish intake to no more than two 6-oz servings a week.