Caesarean before labour between 34 and 37 weeks: what are the risk factors of severe neonatal respiratory distress?

Objective: To assess the frequency of severe neonatal respiratory distress and identify its risk factors in caesarean deliveries before labour between 34 and 37 weeks' gestation.

Study Design: Retrospective study of children born by caesarean delivery before labour between 34 and 37 weeks, between 1999 and 2003 in a level 3 maternity unit. The frequencies of severe and mild neonatal respiratory distress were calculated. Univariate and multivariate analyses studied the factors potentially associated with severe respiratory distress: gestational age, type of pregnancy (singleton or multiple), condition of membranes, maternal diabetes, indication for caesarean, antenatal corticosteroid therapy, intrauterine growth retardation, infant's sex and birth weight.

Results: The 189 study subjects included 107 singletons and 82 twins: 28% required intensive care for severe respiratory distress and 30.2% developed mild respiratory distress. Gestational age was a significant risk factor (p = 0.01), especially before 36 weeks (adjusted OR = 2.1; 95% CI: 1.0-4.4). The multivariate analysis indicated that singleton pregnancies (adjusted OR = 3.2; 95% CI: 1.5-6.7) and caesareans for fetal indications (adjusted OR = 2.7; 95% CI: 1.2-5.7) are also risk factors and that premature rupture of the membranes is a "protective" factor against respiratory complications (adjusted OR = 0.2; 95% CI: 0.1-0.8).

Conclusion: More than a quarter of the infants delivered by caesarean before labour between 34 and 37 weeks' gestation in our level 3 maternity unit had severe respiratory distress. Although our population may not be typical of the general population, this finding and the risk factors associated with it should be taken into account in determining the best time and place for delivery of each patient.