Objectives: The Chilean Government implemented in 1996 a long-running Breastfeeding Promotion Program (BPP) aimed at improving public health personnel's knowledge and skills. In 2011, the government also passed a law that increased maternity leave postpartum (MLE) from 12 to 24 weeks for fully employed women. The possible impact on the exclusive breast feeding (EBF) duration of the BPP and the MLE was studied with an ecological design, analysing grouped data at three and six months of life with representative samples of the population of infants cared for by the country's Ministry of Health outpatient clinics. 
Methods: This ecological study included direct standardizing EBF rates plus Rates Ratio (RR) and Etiological Fraction (EF) calculations. Linear regression models were also performed. 
Results: Selected samples from 1993 until 2019 showed trends of increasing EBF age standardized rates at the third and the sixth months of life in relation to the two national interventions; p-values of the differences were < 0.01 applying the Chi-squared test and Bonferroni as sensitivity analysis. The estimated linear regression models for each intervention and the national annual average trends at six months showed that from 1993-2000 there was no statistically significant trend in the EBF rate or any effect from the BPP intervention. Between 2008-2019, there was a statistically significant increase in the EBF rate. The introduction of MLE showed a significant positive change in the adjusted model.
Conclusion: Results suggest that age standardized EBF rates improve in the first three and six months of life in relation with the two interventions. Further analyses with the regression models indicate that while early interventions such as the BPP may not have yielded measurable outcomes, later initiatives, particularly when coupled with enabling structural conditions like maternity leave policies, appear to have had a significant positive influence.