Fig. 2. International comparison of moderate to severe BPD, severe ROP (≥ stage III), NEC (≥ stage II_a), sepsis, and IVH (≥ grade III) or cystic PVL in VLBWIs with 22–32 weeks' gestation.

BPD = bronchopulmonary dysplasia, ROP = retinopathy of prematurity, NEC = necrotizing enterocolitis, IVH = intraventricular hemorrhage, PVL = periventricular leukomalacia, VLBWIs = very low birth weight infants, KNN = Korean Neonatal Network, CNN = Canandian Neonatal Network, NRNJ = Neonatal Research Network of Japan.

^*P value < 0.05 evaluated with χ² Fisher's exact test, compared with outcomes of the KNN; ^†sepsis at ≥ 3 days of life; ^‡sepsis at ≥ 7 days of life; ^a2013–2016; ^b2006–2008.