Table 1. Characteristics of VLBW infants according to the staging of ROP.
| Characteristics | No ROP (n=1,323) | ROP | P value | |
|---|---|---|---|---|
| Stage ≤2 (n=453) | Stage ≥3 (n=233) | |||
| Maternal characteristics | ||||
| Vaginal delivery | 301 (22.8) | 128 (28.3) | 57 (24.5) | 0.061 |
| PIH | 294 (22.2) | 47 (10.4)* | 32 (13.7)† | < 0.001 |
| Maternal steroid use | 986 (76.0) | 358 (81.2) | 179 (78.5) | 0.075 |
| Maternal GDM | 119 (9.0) | 31 (6.8) | 13 (5.6) | 0.113 |
| Maternal PROM | 434 (32.9) | 201 (44.7)* | 89 (38.2) | < 0.001 |
| Oligohydramnios | 170 (13.7) | 64 (16.0) | 35 (16.4) | 0.386 |
| Chorioamnionitis | 328 (29.4) | 163 (44.7)* | 95 (45.5)† | < 0.001 |
| Neonatal characteristics | ||||
| Gestational age (week) | 29.8 ± 2.4 | 26.9 ± 2.2* | 25.7 ± 1.9†,‡ | < 0.001 |
| Birth weight (g) | 1,1966 ± 216 | 959 ± 244* | 821 ± 245†,‡ | < 0.001 |
| Apgar score at 1 min | 5.1 ± 1.9 | 4.2 ± 1.9* | 3.6 ± 1.7†,‡ | 0.003 |
| Apgar score at 5 min | 7.1 ± 1.6 | 6.5 ± 1.7* | 5.8 ± 1.8†,‡ | < 0.001 |
| Male | 658 (49.7) | 232 (51.2) | 115 (49.4) | 0.843 |
| Neonatal morbidities | ||||
| Pulmonary_air leak | 34 (2.6) | 25 (5.5)* | 15 (6.9)† | < 0.001 |
| Pulmonary hemorrhage | 26 (2.0) | 34 (7.5 )* | 24 (10.3)† | < 0.001 |
| Pulmonary hypertension | 30 (2.3) | 26 (5.7)* | 36 (15.5)†,‡ | < 0.001 |
| RDS | 934 (70.6) | 422 (95.6)* | 232 (99.6)†,‡ | < 0.001 |
| Invasive ventilation days | 8.1 ± 16.6 | 25.8 ± 24.4* | 44.0 ± 39.6†,‡ | < 0.001 |
| Oxygen supplement days | 7.9 ± 12.6 | 12.7 ± 17.3* | 16.6 ± 18.7†,‡ | 0.008 |
| Postnatal steroid use | 149 (11.3) | 226 (49.9)* | 122 (52.4)† | < 0.001 |
| PDA | 482 (36.4) | 283 (62.5)* | 195 (83.7)†,‡ | < 0.001 |
| RBC transfusion | 817 (61.8) | 379 (83.7)* | 219 (94.0)† | < 0.001 |
| NEC (Stage ≥ II) | 32 (2.4) | 31 (6.8)* | 29 (12.4)†,‡ | < 0.001 |
| IVH (Grade ≥ III) | 38 (2.9) | 47 (10.4)* | 43 (18.5)†,‡ | < 0.001 |
| PVL | 72 (5.5) | 68 (15.0)* | 31 (13.4 )† | < 0.001 |
| BPD | 574 (43.6) | 369 (81.6)* | 219 (94.0)†,‡ | < 0.001 |
| Sepsis | 188 (14.2) | 139 (30.7)* | 80 (34.3)† | < 0.001 |
Data are presented as n (%) or mean±standard deviation.*P<0.05, significant; between No ROP and ROP stage≤2; †P<0.05, significant; between No ROP and ROP stage≥3; ‡P<0.05, significant; between ROP stage≤2 and stage≥3. VLBW, very-low-birth-weight; ROP, retinopathy of prematurity; PIH, pregnancy induced hypertension; GDM, gestational diabetes mellitus; PROM, premature rupture of membrane; NICU, neonatal intensive care unit; RDS, respiratory distress syndrome; PDA, patent ductus arteriosus; RBC, red blood cell; NEC, necrotizing enterocolitis; IVH, intraventricular hemorrhage; PVL, periventricular leukomalacia; BPD, bronchopulmonary dysplasia.