The toddlers of mothers who eat fish regularly during pregnancy
may have better language and communication skills by the age of 18
months than those whose mothers never eat fish, a Bristol study has
Fish intake during pregnancy has the potential to improve foetal
development because it is a good source of iron and long-chain
omega fatty acids, which are necessary for the proper development
and function of the nervous system.
The findings follow official warnings to American mothers-to-be
not to eat more than 12 ounces of fish each week because of the
effect of mercury poisoning on their unborn child. But the
researchers at the University of Bristol found that in the UK,
where mercury levels in seafood are relatively low, the benefits of
eating fish in moderation outweighed any risk from
Britain’s Food Standards Agency currently recommends that people
eat at least two portions of fish a week, one of which should be
oily. But prospective mothers are advised to avoid eating shark,
marlin and swordfish and to limit the amount of tuna they
A team from the University of Bristol analysed the diets of
7,400 mothers who are part of the Children of the 90s project, also
known as the Avon Longitudinal Study of Parents and Children
(ALSPAC). The findings are published in the July issue of the
medical journal Epidemiology.
The mothers were asked to record how often they ate fish, and
what type, during pregnancy – and 70 per cent of women said they
ate fish at least once a week.
The researchers studied the children’s cognitive development at
15 and 18 months, looking at standard tests of language,
comprehension and social skills.
Overall the study found that there was a subtle but consistent
link between eating fish during pregnancy and children’s subsequent
test scores, even after adjusting for factors such as the age and
education of the mother, whether she breastfed, and the quality of
the home environment.
The scientists also examined the umbilical cords of 1,200 babies
for presence of mercury. Overall levels were low, and while they
found higher concentrations among women who ate fish, no link was
found in the developmental tests.
The researchers noticed a threshold effect: while there was a
benefit in eating fish in moderation, there was no advantage in
eating large amounts of fish.
The Epidemiology study “Fish intake during pregnancy in relation
to offspring’s early cognitive development,” is by JL Daniels, MP
Longnecker, AS Rowland, J Golding. The ALSPAC study team can be
found at www.alspac.bristol.ac.uk.