Infant mortality due to congenital malformation in Argentina (1998-2009): temporal and spatial analysis of neonatal and postneonatal components.

Abstract

The World Health Assembly (WHO 2010) approved a resolution that called on member states to “prevent birth defects wherever possible, to implement screening programs, and to provide ongoing support and care to children with birth defects and their families.” A resolution was adopted to help redress the limited focus to date on preventing and managing birth defects, especially in low- and middle-income countries. As etiologies differ, infant mortality (IM) was decomposed into two components, the neonatal one covering the first 28 days of life and the postneonatal component comprising the remainder of the first year of life. The neonatal component is preferentially associated with endogenous causes (premature birth, birth sequels, or genetic disorders, among others), and the postneonatal component is concomitant with exogenous factors (infectious diseases, diarrhea, etc.) (Celton and Ribotta 2004). In Argentina, there has been, in recent decades, a significant decrease in IM and its neonatal and postneonatal components associated with a change in the pattern of causes of death, with an increase in those caused by congenital malformations (CM) (WHO 1998). Particularly, the recent pattern (2002–2006) of IM by CM in Argentina is characterized by a decrease in the rate of IM by CM (RIMCM) and concomitant increase in the percentage of deaths from CM (DCM%) (Bronberg et al. 2009). This pattern is similar to that observed in developed countries (Rosano et al. 2000). However, although the spatial distribution is practically uniform RIMCM, especially at the regional and provincial levels, the DCM% displayed wide geographical variation indicative of socio-economic, educational, and cultural interprovincial and interregional inequalities (Bronberg et al. 2012). Previous studies indicate that, between 2002 and 2006 in Argentina, there were variations of the magnitude and trends of the early and late neonatal and postneonatal RIMCM and DCM% components. In the 5-year period under review, there was a steady decline in early neonatal RIMCM while late neonatal and postneonatal remained constant. Higher values of RIMCM occurred in the early neonatal period, followed by the late neonatal and postneonatal. DCM% values in the three components exceeded 20 % with a tendency to progressive involvement of CM in the causes of death (Bronberg et al. 2009). In this study, we found that approximately 1.18/1,000 newborns die from cardiovascular system malformations, and these defects, along with those of the central nervous system, constitute 50 % of all child CM deaths, representing 35.6 % and 14.7 %, respectively (Bronberg et al. 2009). Next in order of magnitude are musculoskeletal system (8.6 %), chromosomal (5.8 %), digestive system (4.5 %), respiratory system (3.0 %), and genitourinary system (2.9 %) malformations (Bronberg et al. 2009). Since knowledge of the temporal and spatial behaviors of neonatal and postneonatal IM by CM in Argentina is still inadequate, this paper proposes a deeper analysis of the secular trend and geographical differences of these components using the RIMCM and DCM%.