Factors associated with premature birth: a case-control study

To analyze the socioeconomic, demographic, environmental, reproductive, behavioral, and health-care factors associated with preterm birth. Case-control study, with case group composed of preterm infants and the control group by full term live births. Each case was paired with two controls according to sex and date of birth. Interviews were carried out with the mothers, as well as analysis of medical records. A logistic regression model was used for data analysis following the hierarchical order of entry of the blocks. 221 live births were allocated in the case group and 442 in the control group. After analysis adjusted for other factors under study, the highest chances of prematurity were associated with being the first child (OR 1.96; 95%CI 1.34-2.86; p=0.001); mothers with the highest income (OR 2.08; 95%CI 1.41-3.08; p