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Low consumption of seafood in early pregnancy as a risk factor for preterm delivery: prospective cohort study

BMJ 2002; 324 doi: (Published 23 February 2002) Cite this as: BMJ 2002;324:447
  1. Sjúrđur Fróđi Olsen (sfo{at}, associate professora,
  2. Niels J⊘rgen Secher, professorb
  1. a Maternal Nutrition Group, Danish Epidemiology Science Centre, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
  2. b Perinatal Epidemiology Research Unit, Department of Obstetrics and Gynaecology, Skejby University Hospital, DK-8200 Aarhus N, Denmark
  1. Correspondence to: S F Olsen
  • Accepted 5 November 2001


Objective: To determine the relation between intake of seafood in pregnancy and risk of preterm delivery and low birth weight.

Design: Prospective cohort study.

Setting: Aarhus, Denmark.

Participants: 8729 pregnant women.

Main outcome measures: Preterm delivery and low birth weight.

Results: The occurrence of preterm delivery differed significantly across four groups of seafood intake, falling progressively from 7.1% in the group never consuming fish to 1.9% in the group consuming fish as a hot meal and an open sandwich with fish at least once a week. Adjusted odds for preterm delivery were increased by a factor of 3.6 (95% confidence interval 1.2 to 11.2) in the zero consumption group compared with the highest consumption group. Analyses based on quantified intakes indicated that the working range of the dose-response relation is mainly from zero intake up to a daily intake of 15 g fish or 0.15 g n-3 fatty acids. Estimates of risk for low birth weight were similar to those for preterm delivery.

Conclusions: Low consumption of fish was a strong risk factor for preterm delivery and low birth weight. In women with zero or low intake of fish, small amounts of n-3 fatty acids—provided as fish or fish oil—may confer protection against preterm delivery and low birth weight.

What is already known on this topic

What is already known on this topic Long chain n-3 fatty acids in amounts above 2 g a day may delay spontaneous delivery and prevent recurrence of preterm delivery

Large studies have not been carried out to determine to what extent low consumption of n-3 fatty acids is a risk factor for preterm delivery

The dose-response relation has not been described

What this study adds

What this study adds Low consumption of fish seems to be a strong risk factor for preterm delivery and low birth weight in Danish women

This relation is strongest below an estimated daily intake of 0.15 g long chain n-3 fatty acids or 15 g fish


  • Funding Novo Nordisk Forskningsfond, Aage-Louis Hansens Fond, Danish National Research Foundation, March of Dimes Birth Defects Foundation, Danish Health Research Foundation, Egmont Fonden.

  • Competing interests None declared.

  • Accepted 5 November 2001
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