Background: Accurate prediction of the prognosis of infants with very low birth weight is beneficial both for their parents and for healthcare professionals.
Methods: This was a population-based study of all low-birth-weight infants admitted to neonatal units in one region in Japan. The Apgar score at 1 and 5 min and neonatal mortality were retrospectively analyzed to obtain the predictive values of the scores. The results were stratified into two categories by birth weight and three time periods (1980-1986, 1987-1993 and 1994-2000).
Results: The predictive values improved in the later years, and therefore only the data obtained in the period 1994-2000 were used. A score of less than 5 at 5 min appears to be a good predictor of neonatal mortality in infants with a birth weight between 1500 g and 2499 g (positive likelihood ratio, 17.59 [95% confidence interval (CI) 12.68-24.40]); however, there is no evidence that the score is a good predictor of neonatal mortality in infants with very low birth weight.
Conclusion: In infants with a low birth weight between 1500 g and 2499 g, an Apgar score at 5 min of less than 5 is a good predictor of neonatal mortality. The score is not useful in predicting the short-term prognosis of very low-birth-weight infants.