Table 1.
The characteristics of the EPIs and their mothers.
| Before matching | After matching | |||||
|---|---|---|---|---|---|---|
| Male (No. = 240) | Female (No. = 199) | P value | Male (No. = 148) | Female (No. = 148) | P value | |
| Neonatal characteristic | ||||||
| Gestational age, weeks | 26.7 (26.0, 27.3) | 26.9 (26.1, 27.4) | 0.115 | 26.9 (26.0, 27.4) | 26.7 (26.0, 27.4) | 0.916 |
| Birth weight, g | 918 (810, 1000) | 870 (760, 950) | <0.01 | 920 (810, 980) | 883 (783, 984) | 0.430 |
| WWLST, No. (%) | 83 (34.6) | 90 (45.2) | 0.023 | 63 (42.6) | 66 (44.6) | 0.725 |
| Apgar score, No. (%) | ||||||
| 1-min ≤3 | 26 (10.8) | 10 (5.0) | 0.027 | 9 (6.1) | 9 (6.1) | 1.000 |
| 1-min 4~7 | 81 (33.8) | 67 (33.7) | 0.986 | 52 (35.1) | 46 (31.1) | 0.459 |
| 5-min ≤7 | 42 (17.5) | 28 (14.1) | 0.329 | 25 (16.9) | 20 (13.5) | 0.418 |
| Mechanical ventilation, No. (%) | 200 (83.3) | 140 (70.4) | <0.01 | 119 (80.4) | 109 (73.6) | 0.167 |
| Duration of mechanical ventilation, days | 4.8 (0.7, 13.5) | 2.7 (0.0, 9.1) | <0.01 | 4.3 (0.5, 12.1) | 3.0 (0.0, 10.0) | 0.088 |
| Maternal characteristic | ||||||
| Age≥35 years old, No. (%) | 80 (33.3) | 46 (23.1) | 0.018 | 42 (28.4) | 37 (25.0) | 0.511 |
| Cesarean section, No. (%) | 79 (32.9) | 71 (35.7) | 0.544 | 49 (33.1) | 41 (27.7) | 0.312 |
| IVF, No. (%) | 95 (39.6) | 85 (42.7) | 0.507 | 57 (38.5) | 65 (43.9) | 0.345 |
| Twin/multiple pregnancy, No. (%) | 63 (26.3) | 66 (33.2) | 0.113 | 47 (31.8) | 56 (37.8) | 0.272 |
| Any antenatal steroids, No. (%) | 155 (64.6) | 136 (68.3) | 0.407 | 105 (70.9) | 94 (63.5) | 0.173 |
| Complete-course antenatal steroids, No. (%) | 69 (28.7) | 84 (42.2) | <0.01 | 60 (40.5) | 51 (34.5) | 0.280 |
| Placental abruption, No. (%) | 24 (10.0) | 18 (9.0) | 0.735 | 13 (8.8) | 13 (8.8) | 1.000 |
| Placenta previa, No. (%) | 16 (6.7) | 12 (6.0) | 0.786 | 8 (5.4) | 10 (6.8) | 0.627 |
| Premature rupture of membranes, No. (%) | 82 (34.2) | 64 (32.2) | 0.657 | 59 (39.9) | 52 (35.1) | 0.401 |
| Chorioamnionitis, No. (%) | 20 (8.3) | 20 (10.1) | 0.534 | 13 (8.8) | 13 (8.8) | 1.000 |
| Intrauterine distress, No. (%) | 9 (3.8) | 7 (3.5) | 0.897 | 8 (5.4) | 5 (3.4) | 0.395 |
| Hypertensive disorder of pregnancy, No. (%) | 27 (11.3) | 38 (19.1) | 0.021 | 19 (12.8) | 17 (11.5) | 0.722 |
| Gestational diabetes mellitus, No. (%) | 42 (17.5) | 35 (17.6) | 0.981 | 23 (15.5) | 28 (18.9) | 0.442 |
| Cervical incompetence, No. (%) | 43 (17.9) | 34 (17.1) | 0.820 | 30 (20.3) | 25 (16.9) | 0.455 |
Data are presented as median (IQR), or number (%); EPIs, extremely preterm infants; IVF, in vitro fertilization; WWLST, withholding or withdrawing life-sustaining treatment.