Table 1. Anthropometric measurement values at birth, and the maternal and neonatal characteristics in each gestational age group.
| 23+0–25+6 weeks (n = 875) |
26+0–28+6 weeks (n = 1,889) |
29+0–31+6 weeks (n = 1,898) |
P-value | |
|---|---|---|---|---|
| Birth weight (g), mean±SD | 732±145 | 1,021±209 | 1,245±204 | <0.001 |
| Length at birth (cm), mean±SD | 32.0±2.5 | 35.7±2.9 | 38.3±2.7 | <0.001 |
| HC (cm), mean±SD | 22.5±1.6 | 25.1±1.7 | 27.2±1.6 | <0.001 |
| Male, n (%) | 467 (53.4) | 993 (52.6) | 944 (49.7) | 0.108 |
| SGA (<10th percentile), n (%) | 70 (8.0) | 140 (7.4) | 269 (14.2) | <0.001 |
| Birth weight z-score, mean±SD | 0.189±0.960 | 0.114±0.869 | -0.448±0.742 | <0.001‡ |
| <-2, n (%) | 27 (3.1) | 46 (2.4) | 61 (3.2) | |
| -2—1, n (%) | 66 (7.5) | 154 (8.1) | 362 (19.1) | |
| ≥-1, n (%) | 782 (89.4) | 1,689 (89.4) | 1,475 (77.7) | |
| Length at birth z-score, mean±SD | 0.112±1.078 | 0.069±1.098 | -0.356±1.110 | <0.001‡ |
| <-2, n (%) | 30 (3.4) | 98 (5.2) | 145 (7.6) | |
| -2—1, n (%) | 82 (9.4) | 153 (8.1) | 309 (16.3) | |
| ≥-1, n (%) | 763 (87.2) | 1,638 (86.7) | 1,444 (76.1) | |
| HC at birth z-score, mean±SD | 0.114±1.125 | 0.174±1.361 | -0.155±0.376 | <0.001‡ |
| <-2, n (%) | 27 (3.1) | 65 (3.4) | 122 (6.4) | |
| -2—1, n (%) | 75 (8.6) | 195 (10.3) | 273 (14.4) | |
| ≥-1, n (%) | 773 (88.3) | 1,629 (86.2) | 1,503 (79.2) | |
| PIH, n (%) | 68 (7.8) | 276 (14.6) | 478 (25.2) | <0.001 |
| Oligohydramnios, n (%)* | 125 (15.9) | 229 (13.3) | 218 (12.4) | 0.053 |
| Prenatal corticosteroids, n (%)** | 367 (42.4) | 870 (46.8) | 920 (49.3) | 0.004 |
| RDS, n (%) | 858 (98.1) | 1,796 (95.1) | 1,410 (74.3) | <0.001 |
| Moderate or severe BPD, n (%)† | 404 (67.0) | 656 (38.6) | 328 (17.8) | <0.001 |
| Death <36 weeks PMA, n (%) | 272 (31.1) | 188 (10.0) | 58 (3.1) | <0.001 |
| BPD or death, n (%) | 677 (77.4) | 844 (44.7) | 386 (20.3) | <0.001 |
* Values are missing in 90 infants in the 23+0–25+6 weeks group, 168 infants in the 26+0–28+6 weeks group, and 138 infants in the 29+0–31+6 weeks group.
** Values are missing in 10 infants in the 23+0–25+6 weeks group, 29 infants in the 26+0–28+6 weeks group, and 138 infants in the 29+0–31+6 weeks group.
† Values are missing in 272 infants in the 23+0–25+6 weeks group, 188 infants in the 26+0–28+6 weeks group, and 58 infants in the 29+0–31+6 weeks group.
‡ P-value for the Kruskal-Wallis test.
HC, head circumference; SGA, small for gestational age; PIH, pregnancy-induced hypertension; RDS, respiratory distress syndrome; PMA, postmenstrual age; BPD, bronchopulmonary dysplasia.