Do very sick neonates born at term have antenatal risks? 1. Infants ventilated primarily for problems of adaptation to extra-uterine life.

AIMS: 1. Ascertain antenatal and intrapartum risk factors for term neonates ventilated primarily for 'perinatal asphyxia'. 2. Describe the neonatal morbidity and mortality.

METHODS: Population-based case control cohort study.

SETTING: Sydney and four large rural/urban health areas in New South Wales.

SUBJECTS: Singleton term infants, no major congenital anomaly: subset of 83 infants ventilated primarily for 'asphyxia' from 182 cases admitted to a tertiary neonatal intensive care unit (NICU) for mechanical ventilation, 550 randomly selected controls. Outcome. Risk factors for case status by maternal, antenatal, labor, delivery, and combined epochs, adjusted odds ratios (OR), 95 per cent confidence intervals (CI), p < 0.05.

RESULTS: Predictors of case status by multivariate epochs: Primigravida (1.8 [1.1, 2.8]), thyroid disease (7.8 [1.1, 57.0]), any antenatal complication (5.1 [3.0, 8.6]), growth restriction (4.2 [1.7, 10.4]), male gender (2.1 [1.3, 3.5]), gestational age >40 weeks (1.9 (1.1, 3.3)), prolonged rupture of membranes (9.7 [1.3, 72.5]), complicated labor (6.6 [3.7, 11.9]), induced labor (2.2 [1.3, 3.9]), prostaglandins 2.46 [1.23, 4.91]), maternal pyrexia (10.8 [2.8, 42.7]), placental hemorrhage in labor (OR 4.24 [1.45, 12.42]), forceps delivery (4.1 [1.9, 8.5]), emergency cesarean section (4.7 [2.6, 8.7]). Twenty case infants (24%) and no control infants died.

CONCLUSIONS: This study has shown maternal and antepartum risk factors for severe neonatal morbidity in term infants. More centers need to become interested in the term baby, so that a larger multicenter study can further elucidate the heterogeneous causal pathways to term neonatal morbidity.