Scientists in Denmark have found that the risk of premature births is greatly reduced if mothers eat oily fish during pregnancy.
The research published in the British Medical Journal showed that the average birth weight and length of pregnancy both appeared to increase in direct relation to the amount of fish that women ate.
Every year over 13 million babies are born prematurely across the world - many in developing countries. Observations of high birth weights and long gestations in the fish-eating community of the Faroe Islands suggested that intake of seafood rich in long chain n-3 fatty acids can increase birth weight by prolonging gestation or by increasing the foetal growth rate.
Researchers in Aarhus, Denmark compiled a questionnaire to assess the levels of fish consumption in almost 9,000 women. They found that just 1.9 per cent of women who ate fish at least once a week had a premature birth, but this increased to 7.1 per cent among women who never ate fish.
Previous research has shown that omega-3 fatty acids, present in oily fish such as mackerel, herring, trout and salmon, can have a beneficial effect on pregnancy. The finding that even low exposures can effect pregnancy corroborates two earlier studies. A reduction in early delivery was seen in women who had received only 0.1g n-3 fatty acids (along with other substances) a day from week 20 of gestation.
In addition, the study noted that several observational studies have found associations between maternal seafood intake and foetal growth rate.
Randomised controlled trials to examine the relationship between consumption of long chain n-3 fatty acids and timing of delivery and premature risk were warranted by the research team.
Authors of the study also suggested that women who do not eat seafood should consider taking fish oil supplements.
It was noted though that many factors other than diet also contribute to premature birth, for example, an often-cited cause is thought to be a 'silent' infection in the uterus which can lead to early contraction, ripening of the cervix and also early breaking of the waters.
High intake of fish is not likely to be able to counteract the effects of infection. However it has been welcomed as a recognition of the significance of nutrition, amongst other life-style factors, in the causes of premature births.