Some long-chain omega-3 fatty acids are essential for optimal neuro-development in the fetus. Fish is a rich source of these nutrients but there have been suggestions that fish could contain toxins like mercury that could be detrimental to brain function. Indeed, the current US governmental recommendations advise not more than three servings of seafood per week for pregnant women, but there may be a danger that such restrictions could be counter-productive and can result in fetal brain malnutrition.
This is quite an issue so the study by Hibbeln et al (Lancet 2007;369:578-85) is a welcome source of information. They investigated 12 000 children whose mothers had recorded how much seafood they ingested during the index pregnancy and measured it against the child's intellectual, social, communication and fine-motor development up to 8 years of age. They found that the lower the seafood intake, the greater the risk of dysfunction. Fish was protective of normal development and function - exactly the opposite of the US advice. On balance, women are not putting their unborn child at risk by eating three or more portions of fish per week.
As Myers & Davidson say in an editorial (Lancet 2007;369:537-8), the dangers of fish-eating in pregnancy have been misrepresented and are misleading and are not based on any evidence of harm.
