Women who eat very little or no fish during early pregnancy are more likely to give birth prematurely, according to a study in Denmark.
A team led by Sj煤r冒ur Fr贸冒i Olsen at the Statens Serum Institut in Copenhagen asked almost 9000 women who were 16 weeks pregnant to complete a questionnaire on their fish-eating habits. They found that low birth weight and premature birth decreased with increased fish consumption.
Just over seven per cent of women who never ate fish had a premature delivery, compared with 1.9 per cent of women who ate fish at least once a week.
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鈥淲e know very little about the causes of preterm birth,鈥� says Olsen. 鈥淚t seems that one factor is the mother鈥檚 intake of the fatty acids [found in fish].鈥�
Premature birth of babies is associated with an increased risk of death and of developing a variety of disorders, such as lung disease. 鈥淲e need to examine associations between maternal diet and these problems,鈥� Olsen says.
Triggering labour
Previous studies have found high birth weights and relatively long pregnancies among women living in fish-eating communities in the Faroe Islands, northwest of Scotland. Other work has also found evidence of a lower rate of premature birth among pregnant women taking fish oil supplements.
鈥淥ne of the nutrients particular to fish, compared with other food, is long-chain n-3 fatty acids,鈥� says Olsen. 鈥淚t is biologically possible that if women have a low consumption of these fatty acids, the delivery action may be triggered more easily.鈥� He speculates that high levels of n-3 fatty acids may reduce production of certain hormones involved in triggering childbirth.
In the UK, about one in 10 pregnancies end with premature labour. Preterm birth is one of the most common causes of death and disability in the country, says Nicholas Europe-Finner at the Royal Victoria Infirmary in Newcastle. There is an urgent need to unravel the causes of premature birth, he says: 鈥淚n many cases, it remains a mystery.鈥�
Olsen is now extending his research to more than 80,000 women in Denmark, in an attempt to tease out further the influence of maternal diet on the length of pregnancy.
Journal reference: British Medical Journal (vol 324, p 447)