Table 1.
Infants’ characteristics and sex difference according to gestational age group.
| Variables | Total enrolled infants | 23–25 weeks of gestation group | 26–29 weeks of gestation group | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Male (n = 1118) | Female (n = 1045) | P | Male (n = 311) | Female (n = 292) | P | Male (n = 807) | Female (n = 753) | P | |
| Gestational age (weeks) | 27+1 (2+0) | 27+1 (2+0) | 0.971 | 24+5 (0+2) | 24+5 (0+2) | 0.752 | 28+0 (1+2) | 28+0 (1+2) | 0.971 |
| Cesarean section | 773 (69.1) | 738 (70.6) | 0.453 | 211 (67.8) | 190 (65.1) | 0.470 | 562 (69.6) | 548 (72.8) | 0.172 |
| Outborn | 47 (4.2) | 37 (3.5) | 0.425 | 10 (3.2) | 11 (3.8) | 0.712 | 37 (4.6) | 26 (3.5) | 0.256 |
| Intrauterine growth restriction | 63 (5.6) | 84 (8.0) | 0.026 | 19 (6.1) | 26 (8.9) | 0.192 | 44 (5.5) | 58 (7.7) | 0.072 |
| Birth weight (g) | 1009 (261) | 946 (259) | <0.001 | 746 (136) | 700 (137) | <0.001 | 1111 (224) | 1041 (230) | <0.001 |
| Height at birth (cm) | 35.5 (3.4) | 34.8 (3.4) | <0.001 | 32.2 (2.3) | 31.8 (2.2) | 0.087 | 36.6 (3.0) | 35.8 (3.1) | <0.001 |
| Head circumference at birth (cm) | 25.1 (2.2) | 24.5 (2.2) | 0.001 | 22.8 (1.3) | 22.4 (1.6) | 0.002 | 25.8 (1.9) | 25.2 (1.8) | <0.001 |
| Weight at discharge (g) | 2553 (954) | 2418 (907) | <0.001 | 2384 (1287) | 2164 (1154) | 0.028 | 2619 (781) | 2516 (770) | 0.009 |
| Height at discharge (cm) | 45.0 (5.1) | 44.2 (5.4) | <0.001 | 43.7 (6.6) | 42.5 (7.0) | 0.057 | 45.4 (4.3) | 44.8 (4.5) | 0.007 |
| Head circumference at discharge (cm) | 32.1 (3.3) | 31.6 (3.5) | <0.001 | 31.4 (4.6) | 30.5 (4.8) | 0.028 | 32.3 (2.7) | 32.0 (2.8) | 0.018 |
| Apgar scores 1 min | 3.3 (1.6) | 3.4 (1.8) | 0.278 | 3.2 (1.6) | 3.1 (1.7) | 0.413 | 4.4 (1.9) | 4.6 (1.8) | 0.070 |
| Apgar scores 5 min | 4.1 (1.9) | 4.1 (1.9) | 0.775 | 5.6 (1.8) | 5.3 (2.0) | 0.064 | 6.7 (1.7) | 6.8 (1.6) | 0.292 |
| Length of stay (days) | 76 (44) | 76 (43) | 0.939 | 88 (62) | 84 (57) | 0.383 | 72 (33) | 74 (37) | 0.306 |
| Duration on ventilation (days) | 43.8 (39.7) | 41.9 (38.8) | 0.241 | 63.2 (50.1) | 52.5 (43.0) | 0.133 | 36.4 (31.8) | 35.8 (35.3) | 0.736 |
Data are presented as n (%) or mean (SD).