string: The following clinical morbidities were analyzed: respiratory distress syndrome [11]; pulmonary hemorrhage; apnea [12]; dependence on oxygen at 28 days of life and/or at 36 weeks of corrected gestational age [13]; patent ductus arteriosus [14]; clinical sepsis [15]; necrotizing enterocolitis [16]; peri-intraventricular hemorrhage (diagnosed by at least one head ultrasound during hospital stay) [17]; periventricular leukomalacia [18]; and retinopathy of prematurity according to The International Classification of Retinopathy of Prematurity [19].