The relationship between delivery mode and mortality in very low birthweight singleton vertex-presenting infants

To investigate the factors associated with caesarean delivery and the relationship between mode of delivery and mortality in singleton vertex-presenting very low birthweight (< or = 1500 g) live born infants.

Observational population-based study.

Data collected from all 28 neonatal departments comprise the Israel National Very Low Birth Weight Infant Database.

2955 singleton vertex-presenting very low birthweight infants registered in the database from 1995 to 2000, and born at 24-34 weeks of gestation.

The demographic, obstetric and perinatal factors associated with caesarean delivery and subsequent mortality were studied. The independent effect of the mode of delivery on mortality was tested by multiple logistic regression.

Mortality was defined as death prior to discharge.

Caesarean delivery rate was 51.7%. Caesarean delivery was directly associated with increasing maternal age and gestational age, small for gestational age infants, maternal hypertensive disorders and antepartum haemorrhage, and was inversely related to premature labour and prolonged rupture of membranes. Factors associated with increased survival were increasing gestational age, antenatal corticosteroid therapy, maternal hypertensive disorders and no amnionitis. Mortality rate prior to discharge was lower after caesarean delivery (13.2% vs 21.8%), but in the multivariate analysis, adjusting for the other risk factors associated with mortality, delivery mode had no effect on infant survival (OR 1.00, 95% CI 0.74-1.33). In a subgroup with amnionitis, a protective effect of caesarean delivery was found.

Caesarean delivery did not enhance survival of vertex-presenting singleton very low birthweight babies. Caesarean delivery cannot be routinely recommended, unless there are other obstetric indications.