title: Pre-pregnant body mass index and recreational physical activity: effects on perinatal mortality in a prospective pregnancy cohort.
abstract: OBJECTIVE
  To examine the effect of maternal pre-pregnant body mass index (BMI) and recreational physical activity on perinatal mortality.
  
  
  METHODS
  A prospective cohort study.
  
  
  METHODS
  The Norwegian Mother and Child Cohort (MoBa), 1999-2008.
  
  
  METHODS
  Singleton pregnancies without congenital anomalies (n = 77 246).
  
  
  METHODS
  Pre-pregnant BMI was classified as underweight (<18.5), normal weight (18.5-24.9), overweight (25-29.9), obese (30-34.9) or morbidly obese (BMI ≥ 35). Risk estimates were obtained by logistic regression and adjusted for confounders.
  
  
  METHODS
  Perinatal death (stillbirth ≥ 22 weeks plus early neonatal death 0-7 days after birth).
  
  
  RESULTS
  An increased risk of perinatal death was seen in obese [odds ratio (OR) 2.4, 95% CI (confidence interval) 1.7-3.4] and morbidly obese women (OR 3.3, 95% CI 2.1-5.1) as compared with normal weight women. In the group participating in recreational physical activity during pregnancy, obese women had an OR of 3.2 (95% CI 2.2-4.7) for perinatal death relative to non-obese women. In the non-active group the corresponding OR was 1.8 (95% CI 1.1-2.8) for obese women compared with non-obese women. The difference in perinatal mortality risk related to obesity between the active and non-active groups was statistically significant (P-value for interaction = 0.046, multiplicative model).
  
  
  CONCLUSIONS
  Maternal obesity was associated with a two- to three-fold increased risk of perinatal death when compared with normal weight. For women with a BMI <30 the lowest perinatal mortality was seen in those performing recreational physical activity at least once a week.
authors: Department of Obstetrics and Gynaecology, Haukeland University Hospital, Bergen, Norway.|Department of Health Promotion and Development, Faculty of Psychology, University of Bergen, Bergen, Norway.
authors: L M
authors: LM
authors: Sorbye
authors: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.|Medical Birth Registry of Norway, Norwegian Institute of Public Health, Bergen, Norway.
authors: K
authors: K
authors: Klungsoyr
authors: Department of Health Promotion and Development, Faculty of Psychology, University of Bergen, Bergen, Norway.
authors: O
authors: O
authors: Samdal
authors: Norwegian National Advisory Unit on Women's Health, Oslo University Hospital, Rikshospitalet, Oslo, Norway.|Department of Psychosomatics and Health Behaviour, Norwegian Institute of Public Health, Oslo, Norway.
authors: K M
authors: KM
authors: Owe
authors: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.|Department of Clinical Sciences, University of Bergen, Bergen, Norway.
authors: N-H
authors: NH
authors: Morken
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015444:Exercise; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008425:Maternal Behavior; D009664:Norway; D009765:Obesity; D050177:Overweight; D054238:Perinatal Mortality; D011247:Pregnancy; D011248:Pregnancy Complications; D011446:Prospective Studies; D011998:Recreation; D012307:Risk Factors
keywords: Body mass index; Norwegian Mother and Child Cohort Study (MoBa); obesity; overweight; perinatal death; recreational physical activity
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