Using logistic regression analysis, two epidemiologic features: twin (PR = 3.27) and birth weight ≤1500g (PR = 0.69), three clinical features: Fi02> 40% (PR = 3.77), hospitalized period> 30days (PR = 2.08) and transfusion (PR = 0.47), two paraclinical features: Pa02> 100 mmHg (PR = 2.61) and pH < 7.35 (PR = 0.24) were found significantly associated with the development of ROP.