Submitted by: John Bart, MD, Toronto, Ontario
Routine screening of mercury levels in the general population is not recommended. Testing is appropriate if a patient is at risk because of frequent consumption of fish that may contain elevated levels of mercury (e.g., shark, tilefish, swordfish, and king mackerel) or has symptoms. When elevated mercury levels are detected, the individual should be advised to reduce her intake of mercury-containing fish. Mercury levels will decline rapidly within three weeks of reduced intake.1 Once mercury levels normalize, there is no longer a risk to the fetus. Recommended fish consumption for pregnant women is no more than two 6 oz. servings per week of fish low in mercury.2 Fish are an excellent source of omega-3 fats and docosahexaenoic acid, which are important to early brain development.
1. Hightower JM, Moore D: Mercury Levels in High-end Consumers of Fish. Environ Health Perspect 2003; 111(4):604–608.
2. Food and Drug Administration. Consumer Advisory: An Important Message for Pregnant Women and Women of Childbearing Age Who May Become Pregnant about the Risks of Mercury in Fish. www.fda.gov/OHRMS/DOCKETS/ac/02/briefing/3872_Advisory 1.pdf. Accessed: December 13, 2013.
