[Neonatal weight: an analysis of the distribution]

We examined birthweight distribution in relation to gestational age from 25 to 42 weeks in a series of 3.526 single newborns and in whom reliability of gestational age was rigorously controlled. To verify the distribution normality the Shapiro-Wilk and the Kolmogorov tests have been applied. Birthweight data follow a gaussian distribution for each gestational age week. Therefore in the birthweight standards estimation the parametric method can safely be applied also when the series includes pathologic and preterm newborns.