Developmental tempo in children aged 0-5 years living under unfavourable environmental conditions.

OBJECTIVE: To describe the dynamics of development along the early years of life among children living under unfavorable socioeconomic conditions. POBLACION Y METODOS: En 5401 ninos menores de 6 anos de zonas con alta proporcion de poblacion con necesidades basicas insatisfechas de Florencio Varela y de la Cuenca Matanza-Riachuelo (Matanza, Villa 21-24, Wilde, Villa Inflamable y Acuba), se estimo, por regresion logistica, la edad mediana de cumplimiento de 13 pautas de desarrollo psicomotor y se graficaron, en el eje de las "y", las diferencias entre esas edades y las de la referencia nacional, y, en el eje de las "x", la edad mediana segun la referencia nacional. RESULTS: Three stages were observed: the first one between 0 and 270 days with normal development, in which the median age at attainment was similar to that of the national reference; a second one of progressive development delay; and a third one of recovery at 1260 days. Adjusted linear spline slopes were 0.06 (not significant), -0.26 (p < 0.0001) and 0.26 (p < 0.01) for stages 1, 2 and 3, respectively. The three slopes were statistically different from each other. The stage of normal development (stage 1) was attributed to the protective effect of the mother and the family environment; stage 2 of progressive delay, to the unfavorable impact of the environment, and stage 3 of partial recovery was attributed to attending a daycare center. These findings allow the implementation of effective interventions at each stage. CONCLUSION: Se identificaron tres periodos con diferente tempo de desarrollo.