Neonatal outcome of inborn and outborn extremely low birth weight infants: relevance of perinatal factors.

BACKGROUND: A substantial number of premature deliveries occur in hospitals lacking neonatal intensive care facilities. We previously demonstrated a comparable outcome of very low birth weight infants delivered in a level II nursery to that of inborn infants delivered in our tertiary care center, but a similar comparison of extremely low birth weight infants has not been done.

OBJECTIVES: To compare the neonatal outcome (mortality, severe intraventricular hemorrhage/periventricular leukomalacia, bronchopulmonary dysplasia and intact survival) of inborn and outborn ELBW infants, accounting for sociodemographic, obstetric and perinatal variables.

METHODS: We compared 97 ELBW infants (birth weight < or = 1000 g) delivered between the years 2000 and 2004 in a hospital providing neonatal intensive care to 53 ELBW babies delivered in a referring hospital. A univariate model was first applied to examine the associations of the individual independent variables with the outcome variable, followed by a logistic stepwise regression analysis for each of the outcome variables. The odds ratios for each predictor were reported as well as their P values and 95% confidence intervals.

RESULTS: In the stepwise logistic regression analysis, accounting for a possible confounding effect of the independent variables, 'hospital of birth' remained a statistically significant predictor in the final step only for mortality, with odds ratio (inborns relative to outborns) of 3.32 (95% CI 1.19-9.28, P = 0.022). No statistically significant associations with the other outcome variables were found (severe IVH/PVL odds ratio = 1.99, 95% CI = 0.77-5.14, P = 0.155; BPD odds ratio = 0.60, 95% CI = 0.19-1.91, P= 0.384; intact survival OR = 0.56, 95% CI = 0.23-1.35, P = 0.195).

CONCLUSIONS: ELBW outborn infants may share an outcome comparable with that of inborn babies, if adequate perinatal care is provided.