“…Clinical data were collected from patients' medical records and included mother's age, presence of premature rupture of membranes (PROM), histological chorioamnionitis, antenatal glucocorticoid use, ritodrine hydrochloride use, magnesium sulfate use, gestational week at birth, birth weight, sex, RDS (chest radiograph consistent with Bomsel criteria, grades 2-4) [15], Apgar score at 1 and 5 min, delivery by caesarean section (C-section), surfactant treatment, whether the child was small for gestational age (SGA, birth weight <10th percentile or median birth weight at same gestational age in Japanese newborns) [16], and ventilator treatment.…”