Severe respiratory disorders in term neonates.

Few prospective population-based studies of respiratory diseases have been conducted in term neonates. We aimed to describe mechanically ventilated respiratory disorders in term neonates and associated risk factors in a regional-based study of livebirths between 37 and 41 weeks. The study was prospective for epidemiological data recording, and retrospective for collecting additional data from charts of neonates with severe (mechanically ventilated) respiratory disorders. A total of 14,813 neonates with gestational age (GA) 37-38 weeks and 50,187 neonates with GA 39-41 weeks were included. The overall incidences (per thousand livebirths) of mechanically ventilated transient tachypnoea of the newborn (TTN) respiratory distress syndrome (RDS) and meconium aspiration syndrome (MAS) were 0.72 per thousand[95% CI 0.53 per thousand, 0.96 per thousand], 0.38 per thousand[95% CI 0.25 per thousand, 0.57 per thousand] and 0.61 per thousand[95% CI 0.44 per thousand, 0.84 per thousand], respectively. Increasing GA from 37 to 41 weeks was associated with a significant decrease in incidence of RDS and TTN without any significant change for MAS. Multivariable analysis was used to identify independent factors associated with severe respiratory disorders: in the 37-38 weeks group - Apgar score < or =3 at 1 min, elective caesarean section (CS), emergency CS and placental abruption; in the 39-41 weeks group - Apgar score < or =3 at 1 min, elective CS, emergency CS, meconium-stained amniotic fluid and abnormal cardiotocography. Comparing the population attributable risks, the main risk factor of severe respiratory disorders was elective CS in the 37-38 weeks group and meconium-stained amniotic fluid in the 39-41 weeks group.