WASHINGTON – In a major break with current U.S. health advice, a coalition of top scientists from private groups and federal agencies plans to advise pregnant and breast-feeding women to consume at least 12 ounces of fish and seafood per week to ensure optimal brain development of their babies.

That recommendation, which will be announced at a news conference today, essentially is at odds with the standard government advice since 2001 that these groups should eat no more than 12 ounces of seafood a week because of concerns about mercury contamination.

The new advisory comes from the National Healthy Mothers, Healthy Babies Coalition – a nonprofit group with nearly 150 members, including the American Academy of Pediatrics, the March of Dimes, the National Institute on Child Health and Human Development and the Centers for Disease Control and Prevention.

Concerns over the impact of fish on the brain development of fetuses and infants, the most vulnerable groups, have been one of the more vexing nutritional dilemmas of recent years, causing widespread consumer confusion and fueling much scientific debate.

“It’s been an important issue over the last decade or so,” said Brown University professor Patricia Nolan, former director of the Rhode Island Department of Health and one of the experts who drafted the new guidelines. “There is a big debate about what is safe … There are really complex questions. That is why we are doing this.”

Concerns about mercury contamination prompted the Food and Drug Administration and the Environmental Protection Agency to issue warnings in 2001 and 2004. Pregnant and breast-feeding women, those who want to become pregnant and young children were advised to eat no more than 12 ounces weekly of seafood, based on theoretical calculations of the potential for contamination. Exposure of too much methyl mercury has been linked to neurological problems.

The FDA and EPA also recommended that these groups avoid eating shark, tilefish, king mackerel and swordfish because of their high mercury content and limit albacore tuna to no more than six ounces per week.

But recent studies have suggested that the health benefits of fish and seafood outweigh the potential health risks from mercury. Based on that evidence, a number of countries and governmental groups including United Kingdom, Australia, Belgium, the Netherlands and the Nordic Council of Ministers, already advise that pregnant women eat at least a couple of servings of fish weekly. Fish and seafood are the major dietary sources of omega-3 fatty acids, especially a substance called docosahexaenoic acid, or DHA, that are key nutrients for brain and nervous systems in the developing fetus and in babies and young children.

Some of the most compelling evidence for the importance of including seafood in the diet of pregnant women came earlier this year from the Avon Longitudinal Study of Parents and Children in the United Kingdom. In February, a team of scientists from the University of Bristol in the United Kingdom and the U.S. National Institute on Alcohol Abuse and Alcoholism reported in the journal the Lancet that the children of women who ate little fish during pregnancy had lower IQs and more behavioral and social problems than youngsters whose mothers ate plenty of seafood.

Other research has suggested that these healthy fats also appear to decrease the risk of delivering a preterm, low birth-weight baby.

It’s not just babies and children who may be helped. Other recent research suggests that higher seafood consumption during pregnancy is linked with a lower risk of depression in the mother both during pregnancy and immediately after giving birth. An estimated one in every 10 new mothers experiences post-partum depression, according to James McGregor, a University of Southern California obstetrician who headed the Maternal Nutrition Group for the Healthy Mothers, Healthy Babies Coalition.