SciELO - Scientific Electronic Library Online

 
vol.23 issue1In search of the origin of municipal pharmacists author indexsubject indexarticles search
Home Page  

Gaceta Sanitaria

Print version ISSN 0213-9111

Abstract

RAMOS, Francisca; PEREZ, Glória; JANE, Mireia  and  PRATS, Ramon. Construction of the birth weight by gestational age population reference curves of Catalonia (Spain): Methods and development. Gac Sanit [online]. 2009, vol.23, n.1, pp. 76-81. ISSN 0213-9111.  http://dx.doi.org/10.1590/S0213-91112009000100016.

Infant size at birth is a useful indicator to evaluate fetal growth in relation to gestational age. There is no standard model to create anthropometric reference curves in neonates, but the method chosen could determine the reference values estimated. We describe the methods used to construct population-based reference curves of birth weight for gestational age in Catalonia, Spain. These methods included detection of implausible values of birth weight for gestational age by a probabilistic cluster model, utilization of the Generalized Additive Model for Location and Scale method to obtain smoothed percentiles and z-scores, and calculation of 95% confidence intervals by bootstrapping. To our knowledge, these are the first reference curves in neonates constructed through a method allowing asymmetric distributions with kurtosis to be modelled. Estimation of confidence intervals is useful to determine which reference intervals can be employed to assess newborn size.

Keywords : Growth curves; Implausible values; Smoothing; Skewness; Kurtosis; Confidence intervals.

        · abstract in Spanish     · text in English     · pdf in English