Effect of pregestational maternal, obstetric and perinatal factors on neonatal outcome in extreme prematurity

PURPOSE: To investigate the effect of pregestational maternal, obstetric and perinatal factors on neonatal outcome in extreme preterm deliveries. METHODS: Retrospective study of deliveries in a Norwegian tertiary teaching hospital. All women with live births at 24(+0)– 27(+6) weeks of gestation between 2004 and 2007 were included. Major morbidity is defined as intraventricular haemorrhage grade 3–4, periventricular leukomalacia, bronchopulmonary dysplasia or necrotizing enterocolitis. Pregestational maternal, obstetric and perinatal variables were initially compared for mortality and survival with major morbidity at 24-h, 7- or 28-day postpartum/discharge in univariate analysis. Then, a multivariate analysis was conducted in order to determine independent factors associated with mortality and survival with major morbidity. RESULTS: A total of 109 babies were delivered alive in 92 women, representing 1.6% of total births. The survival rates were 93.6, 84.4 and 80.7%, with a prevalence of major morbidity among survivors of 40.4, 32.1 and 39.4% at 24-h, 7- and 30-day postpartum/discharge, respectively. After adjustment using multiple logistic regression, only a 5-min Apgar score ≤3 and babies with at least one major morbidity had significantly independent effects on neonatal survival. Multiple pregnancy and gestational age <26 weeks were the only two independent risk factors for survival with major morbidity. CONCLUSIONS: Neonatal survival was significantly predicted by a 5-min Apgar score and neonatal morbidity, independent of pregestational maternal disease, obstetric complications, method of delivery, gestational age and birth weight in extreme preterm deliveries. The excess morbidity rate was confined among multiples and babies who were delivered before 26 weeks of gestation.