title: Risk of childhood asthma and allergic rhinitis in relation to pregnancy complications.
abstract: BACKGROUND
  Events occurring during fetal life may affect the development of the immune and respiratory systems and increase the risk of asthma and allergic diseases.
  
  
  OBJECTIVE
  We sought to elaborate the relations between the occurrence of pregnancy complications and other pregnancy-related conditions and the risk of bronchial obstruction during the first 2 years of life and the occurrence of asthma and allergic rhinitis by the age of 4 years. Pregnancy complications were considered both as predictors of the health outcomes and as possible effects caused by other prenatal factors.
  
  
  METHODS
  A population-based, 4-year, cohort study was carried out involving 2531 children born in Oslo, Norway. We collected information on maternally related (hyperemesis, hypertension, and preeclampsia) and uterus-related complications in pregnancy (antepartum hemorrhage, preterm contractions, insufficient placenta, and restricted growth of the uterus) and the child's health and environmental exposures at birth and at 6, 12, 18, and 24 months and 4 years of age. The outcomes of interest were bronchial obstruction during the first 2 years and asthma and allergic rhinitis at the age of 4 years.
  
  
  RESULTS
  In a logistic regression analysis adjusting for potential confounders, uterus-related, but not other pregnancy-related, complications increased the risk of bronchial obstruction (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.3-3.4), asthma (OR, 3.0; 95% CI, 1.8-5.4), and allergic rhinitis (OR, 2.9; 95% CI, 1.6-5.2). These relations were similar in children of atopic and nonatopic parents.
  
  
  CONCLUSIONS
  Uterus-related complications in pregnancy increase the risk of having asthma and allergic rhinitis in childhood.
authors.affiliation: Section of Epidemiology, Department of Population Health Sciences, National Institute of Public Health, Oslo, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Nafstad
authors.forename: P
authors.initials: P
authors.lastname: Magnus
authors.forename: J J
authors.initials: JJ
authors.lastname: Jaakkola
mesh_terms: D000328:Adult; D001249:Asthma / Q000209:etiology / Q000235:genetics / Q000276:immunology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008173:Lung Diseases, Obstructive / Q000209:etiology; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000276:immunology*; D011446:Prospective Studies; D012221:Rhinitis, Allergic, Perennial / Q000209:etiology / Q000235:genetics / Q000276:immunology*; D012307:Risk Factors; D011795:Surveys and Questionnaires