title: Maternal intake of seafood and supplementary long chain n-3 poly-unsaturated fatty acids and preterm delivery.
abstract: BACKGROUND
  Preterm delivery increases the risk of neonatal morbidity and mortality. Studies suggest that maternal diet may affect the prevalence of preterm delivery. The aim of this study was to assess whether maternal intakes of seafood and marine long chain n-3 polyunsaturated fatty acids (LCn-3PUFA) from supplements were associated with preterm delivery.
  
  
  METHODS
  The study population included 67,007 women from the Norwegian Mother and Child Cohort Study. Maternal food and supplement intakes were assessed by a validated self-reported food frequency questionnaire in mid-pregnancy. Information about gestational duration was obtained from the Medical Birth Registry of Norway. We used Cox regression to estimate hazard ratios (HR) with 95% confidence intervals (CI) for associations between total seafood, lean fish, fatty fish, and LCn-3PUFA intakes and preterm delivery. Preterm was defined as any onset of delivery before gestational week 37, and as spontaneous or iatrogenic deliveries and as preterm delivery at early, moderate, and late preterm gestations.
  
  
  RESULTS
  Lean fish constituted 56%, fatty fish 34% and shellfish 10% of seafood intake. Any intake of seafood above no/rare intake (>5 g/d) was associated with lower prevalence of preterm delivery. Adjusted HRs were 0.76 (CI: 0.66, 0.88) for 1-2 servings/week (20-40 g/d), 0.72 (CI: 0.62, 0.83) for 2-3 servings/week (40-60 g/d), and 0.72 (CI: 0.61, 0.85) for ≥3 servings/week (>60 g/d), p-trend <0.001. The association was seen for lean fish (p-trend: 0.005) but not for fatty fish (p-trend: 0.411). The intake of supplementary LCn-3PUFA was associated only with lower prevalence of early preterm delivery (before 32 gestational weeks), while increasing intake of LCn-3PUFA from food was associated with lower prevalence of overall preterm delivery (p-trend: 0.002). Any seafood intake above no/rare was associated with lower prevalence of both spontaneous and iatrogenic preterm delivery, and with lower prevalence of late preterm delivery.
  
  
  CONCLUSIONS
  Any intake of seafood above no/rare consumption was associated with lower prevalence of preterm delivery. The association was stronger for lean than for fatty fish. Intake of supplementary LCn-3PUFA was associated only with early preterm delivery. The findings corroborate the current advice to include fish and seafood as part of a balanced diet during pregnancy.
authors.affiliation: Department of Environmental Exposure and Epidemiology, Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, NO-0403, Oslo, Norway. AnneLise.Brantsaeter@fhi.no.
authors.forename: Anne Lise
authors.initials: AL
authors.lastname: Brantsæter
authors.affiliation: Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Englund-Ögge
authors.affiliation: Department of Environmental Exposure and Epidemiology, Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, NO-0403, Oslo, Norway.
authors.forename: Margareta
authors.initials: M
authors.lastname: Haugen
authors.affiliation: Unit for Nutrition Research, Landspitali University Hospital and University of Iceland, Reykjavik, Iceland.
authors.forename: Bryndis Eva
authors.initials: BE
authors.lastname: Birgisdottir
authors.affiliation: Department of Environmental Exposure and Epidemiology, Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, NO-0403, Oslo, Norway.
authors.forename: Helle Katrine
authors.initials: HK
authors.lastname: Knutsen
authors.affiliation: Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Verena
authors.initials: V
authors.lastname: Sengpiel
authors.affiliation: Department of Genetics and Bioinformatics, Domain of Health Data and Digitalisation, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Ronny
authors.initials: R
authors.lastname: Myhre
authors.affiliation: Office of the Director-General, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Jan
authors.initials: J
authors.lastname: Alexander
authors.affiliation: Department of Health and Social Sciences, Bergen University College, Bergen, Norway.
authors.forename: Roy M
authors.initials: RM
authors.lastname: Nilsen
authors.affiliation: Department of Genetics and Bioinformatics, Domain of Health Data and Digitalisation, Norwegian Institute of Public Health, Oslo, Norway.|Department of Obstetrics and Gynecology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
authors.forename: Bo
authors.initials: B
authors.lastname: Jacobsson
authors.affiliation: Department of Environmental Exposure and Epidemiology, Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, NO-0403, Oslo, Norway.
authors.forename: Helle Margrete
authors.initials: HM
authors.lastname: Meltzer
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004034:Diet Surveys / Q000379:methods; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D004435:Eating; D015525:Fatty Acids, Omega-3 / Q000627:therapeutic use*; D005260:Female; D005865:Gestational Age; D006801:Humans; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D039401:Prenatal Nutritional Physiological Phenomena; D015995:Prevalence; D016016:Proportional Hazards Models; D012042:Registries; D017747:Seafood / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D015525:Fatty Acids, Omega-3
keywords: Food frequency questionnaire; MoBa; Preterm delivery; Seafood consumption; The Norwegian Mother and Child Cohort Study