Flowchart of the study population, data source and study groups. Source: Information System of Live Births and Records of pregnant women in Primary Health Care Units and Clinics Hospital. A total of 8,442 live newborns including 860 LBW newborns were born during the study period. The case group consisted of all LBW newborns, as defined by the WHO , that were born during the study period. The control group consisted of a random sample of 860 live newborns weighing greater than or equal to 2,500 grams. After establishing the two groups, the analysis of ANC adequacy was performed for all newborns that were recorded on the medical charts of pregnant women that received ANC in health units registered in the SUS.