P2-384 Risk of preterm birth: a case-control population-based

The prevalence of preterm birth has increased in recent years and is a worldwide public health problem. To study the risk factors for preterm birth we examined hospital deliveries in residents in the city of Campina Grande/PB, Brazil. The case-control population-based study was conducted from June 2008 to May 2009. The medical data and interviews of mothers of 341 preterm births (cases) and 424 controls were conducted. Logistic multiple regression model, based on a hierarchised conceptual modelling, approach was performed. The risk factors for preterm birth were: previous preterm birth (OR=2.32; 95% CI 1.25 to 4.29), inadequate prenatal care (category II - three or more negative prerequisites) (OR=2.15; 95% CI 1.40 to 3.27), inadequate maternal weight gain (OR=2.33; 95% CI 1.45 to 3.75), physical damage to the mother during pregnancy (OR=2.10; 95% CI 1.22 to 3.60), hypertension pressure (OR=17.08; 95% CI 3.67 to 79.43), hospitalisation during pregnancy (OR=5.64; 95% CI 3.47 to 9.15), amniotic fluid volume changes (OR=2.28; 95% CI 1.32 to 3.95), vaginal bleeding (OR=1.54; 95% CI 1.01 to 2.34) and multiple gestation (OR=22.65; 95% CI 6.22 to 82.46). The per capita income less than the minimum wage was a protective factor (OR=0.63; 95% CI 0.39 to 0.99). The risk factors were similar to those observed in other national and international studies, except for the result of varying socioeconomic level. The high prevalence of poverty and low educational level, higher than in studies in the South in both outcomes, may have contributed to this result. Further studies are needed on the complexity of causal chains in preterm delivery in different contexts and differentiation by subtypes (spontaneous and indicated pre-term births).