Table 2. Clinical characteristics.
| Variables | Period 1 (n=37) | Period 2 (n=50) | Period 3 (n=37) | P value |
|---|---|---|---|---|
| Gestational age (wk) | 29+5±2+5 | 29+1±2+2 | 29+4±2+0 | 0.533 |
| Birth weight (g) | 1,135±252 | 1,120±222 | 1,168±212 | 0.673 |
| Birth height (cm) | 37.2±3.0 | 36.3±3.0 | 37.0±2.6 | 0.398 |
| Birth head circumference (cm) | 26.5±1.9 | 26.2±1.8 | 26.6±1.9 | 0.589 |
| Multiple births | 10 (27.0) | 10 (20.0) | 9 (24.3) | 0.736 |
| Male sex | 22 (59.5) | 32 (64.0) | 22 (59.5) | 0.878 |
| Apgar score at 1 min | 5.4±1.7 | 5.5±1.6 | 6.1±1.4 | 0.128 |
| Apgar score at 5 min | 7.7±0.8 | 7.5±1.0 | 7.7±1.6 | 0.305 |
| Antenatal steroid use | 12 (32.4) | 22 (44.0) | 23 (62.2) | 0.035 |
| Surfactant use | 27 (73.0) | 36 (72.0) | 22 (59.5) | 0.362 |
| PDA treatment | 16 (43.2) | 17 (34.0) | 10 (27.0) | 0.339 |
Values are presented as mean±standard deviation or number (%).
P values were determined using the chi-square test or Kruskal-Wallis test as appropriate.
PDA, patent ductus arteriosus.