This study focuses on the repercussions of prematurity for the growth and development of newborns from hospitals in Guadalajara, Jalisco, México, typical of the health care system in México. Infants were assessed every six months as to nutritional status and the Denver Selective Test. In analyzing the results, social groups were considered determinant categories for studying prematurity as the dependent variable. The results shows that both prematurity and social group are risk factors to be considered by the public health field when designing health care programs.