[Efficacy of a national program to promote breast feeding: Chile 1993-2002].

Promotion of breast feeding is a priority in Chilean health's policies. The aim of the study was to evaluate the tendency of breastfeeding (exclusive, continued, partial), in children less than 18 months old, controlled in the Chilean public health system, based in four national surveys. Through a 24 h food intake recall (breastfeeding, water, juice, infant formula, solids) food patterns were explored every 3 years, as well as maternal participation in jobs located away from home. the sample consisted of approximately 10 thousand children, less than 18 months old of the 28 health services throughout the country. The prevalence of children with exclusive breastfeeding, predominant (breastfeeding, water or juice), complemented (breastfeeding plus solids) or any other way of feeding for each month of age in each survey, and changes in period studied, was determined. Between 1993 and 2002, exclusive breastfeeding for 6 months increased from 16 to 43.1% (p<0.001) and predominant breastfeeding from 25.4 to 57.4%. at the same time, complemented breastfeeding at 12 months increased from 10.7 to 21.3%, and partial or complemented breastfeeding in 12 to 18 month old children went from 24.1 to 46.7%. Maternal work located away from home was inversely associated with the prevalence of exclusive and complemented breastfeeding during the first year (p<0.001). There has been a significant increase of maternal breastfeeding in the period analyzed. The negative effects of maternal labor on breastfeeding suggests to explore more effective forms of social support to the working mother.