title: Occurrence and severity of bronchopulmonary dysplasia and respiratory distress syndrome after a preterm birth.
abstract: BACKGROUND
  Despite notable advances in neonatal care, bronchopulmonary dysplasia (BPD) remains an important complication of preterm birth, frequently resulting in prolonged hospital stay and long-term morbidity.
  
  
  METHODS
  A historical cohort study of all preterm infants (gestational age younger than 37 weeks) admitted to the Montreal Children's Hospital (Montreal, Quebec) between January 1, 1980, and December 31, 1992, was conducted. Information collected included demographic data, maternal and perinatal history, and main neonatal outcomes. Independent risk factors associated with BPD were identified by univariate analysis using one-way ANOVA, t tests or Mantel-Haenszel χ(2) testing. Severity of disease was studied using an ordinal multinomial logistic regression model.
  
  
  RESULTS
  In total, 1192 preterm infants were admitted, of whom 551 developed respiratory distress syndrome and 322 developed BPD. For each additional week of prematurity, the risk of developing BPD increased by 54% (adjusted OR 1.54/week [95% CI 1.45 to 1.64]). For each point subtracted on the 1 min Apgar score, the risk of developing BPD was increased by 16% (OR 1.16 [95% CI 1.1 to 1.3]). BPD was also associated with the presence of patent ductus arteriosus (OR 3.5 [95% CI 2.1 to 6.0]), pneumothorax in the first 48 h (OR 9.4 [95% CI 3.6 to 24.8]) or neonatal pneumonia/sepsis in the neonatal period (OR 1.9 [95% CI 1.1 to 3.2]). Severity of BPD was associated with gestational age, 1 min Apgar score, very low birth weight and the presence of neonatal pneumonia/sepsis.
  
  
  CONCLUSIONS
  Factors associated with BPD following a preterm birth were the degree of prematurity, birth weight, Apgar score at 1 min, and the presence of patent ductus arteriosus, pneumothorax or neonatal pneumonia/sepsis.
authors.affiliation: Respiratory Epidemiology & Clinical Research Unit, McGill University, Montreal, Quebec.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Landry
authors.forename: Dick
authors.initials: D
authors.lastname: Menzies