Recently, Wenstrom KD of Alpert Medical School’s Department of Obstetrics and Gynecology focused on how pregnant and lactating women choose to consume fish and published the article in the journal Am J Obstet Gynecol. In June 2014, the U.S. Food and Drug Administration (FDA), in conjunction with the Environmental Protection Agency, issued an updated draft of recommendations for fish consumption by pregnant and lactating women. A recent survey showed that 21% of pregnant women did not eat fish in the first month of pregnancy and 75% of pregnant women consumed only <4 oz/week of fish. They are considered to be deficient in nutrients important for fetal growth and development. Presumably, many women decide not to eat fish during pregnancy because of potential mercury contamination of fish, among other reasons. A dietary guideline is proposed in the draft. It provides a table listing the milligram amounts of omega-3 fatty acids (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), and the amount of mercury in various 4 oz. fish. This information does not seem to suggest that women need to avoid fish during pregnancy and lactation, but rather that women should eat more fish with high fatty acid levels and low mercury levels. omega-3 fatty acids are important components of all cell membranes in the body and maintain proper function and transport of membrane fluidity and membrane-bound enzymes. omega-3 fatty acids are essential for brain and retinal tissues (especially myelin and retinal photoreceptor cells) for normal development and maintenance of normal neurotransmission and connectivity. As the human fetus develops into late gestation, DHA serves as a reservoir of water needed for the body fat layer and other fatty acids, while participating in brain development and metabolism. Maternal intake of adequate amounts of fish (defined in many studies as at least 340 grams of fatty fish/week) is associated with better child IQ, coordinated fine motor skills, better communication and social skills, and a reduced incidence of postpartum depression. Fatty acids synthesize a variety of anti-inflammatory and inflammatory substrates, and also facilitate changes in thromboxane and prostaglandins, which may explain the longer gestation period and higher birth weight. Omega-3 fatty acids may also improve cardiovascular health by preventing fatal arrhythmias, lowering triglyceride and C-reactive protein levels, the Centers for Disease Control and Prevention monitors serum DHA and EPA as an indicator of a healthy diet, and the American Heart Association recommends high intakes of omega-3 fatty acids as a heart-healthy diet. FDA recommendations do not specify a daily intake of omega-3 fatty acids. The U.S. Environmental Protection Agency has determined that a safe intake of methylmercury during pregnancy is 0.1 mg/kg per day, approximately 6-8 mg/day, and 42-64 mg/week. the FDA recommends that pregnant and lactating women not eat squareheads, shark, swordfish, and mackerel because they have the highest mercury levels (100-220 mg per 4 oz). The FDA also specifically recommends limiting consumption of albacore tuna to 6 ounces per week. Although farmed fish tend to contain small amounts of mercury compared to wild-caught fish, they contain high levels of polychlorinated biphenyls (PCBs) and dioxins. PCBs in fish from polluted lakes (such as the Great Lakes) can be unacceptably high; prenatal PCB exposure can cause lower verbal IQ scores. In the U.S., saltwater fish are usually mercury-free, so fish can be eaten during pregnancy, but 4 ounces of fish contain only 100 mg of DHA and EPA. While omega-3 fatty acids or fish oil supplements seem like a very good way to get DHA and EPA - without risking exposure to mercury and other toxic substances. the FDA draft also says that the nutrients provided by fish may be beneficial to fetal and child development overall. If women do not eat fish during pregnancy, taking omega-3 fatty acid supplements may miss out on many other important nutrients that the body needs. Randomized controlled trials have found that prenatal omega-3 fatty acid or fish oil supplementation did not consistently improve cognitive, language or motor skills in children, nor was it beneficial for cardiovascular health. Fish may have a cumulative positive effect of all nutrients. In dietary supplements of DHA and EPA, researchers have not found naturally occurring forms of the same metabolic properties. Concentrated fish oil is particularly low in stability and tends to deteriorate, and consumption of antioxidants induces free radical formation. FDA recommends that because fish contains omega-3 fatty acids that are essential for fetal brain development, pregnant and lactating women should eat more fish. However, they should not eat fish with high mercury content and be cautious about eating wild fish (if the level of contaminants in the water is unknown to the person consuming it), but should instead choose fish with relatively high levels of DHA and EPA, although the optimal daily dose of DHA and EPA is unknown.