Risk estimates for spontaneous preterm birth according to some conditions during pregnancy, comparing women who delivered prematurely (CASES) and women who delivered at term (CONTROLS).

OR*: Odds Ratio adjusted for the cluster effect design; CI: confidence interval; PHU: Primary Health Unit. (#) Severe and/or complicated cases of maternal hypertension or diabetes that indicated an interruption of pregnancy prematurely were contemplated in therapeutic preterm birth, so excluded from this analysis. (*) Severe cases of foetal growth restriction that indicated an interruption of pregnancy prematurely were contemplated in therapeutic preterm birth, so excluded from this analysis. Values in bold mean they are statistically significant. Risk estimates for spontaneous preterm birth according to some conditions during pregnancy, comparing women who delivered prematurely (CASES) and women who delivered at term (CONTROLS).