| Gestational age, wk, mean (range) |
25.3 (23.0–27.9) |
| Birth weight, g, mean (range) |
726 (400–987) |
| Birth weight z-score, mean (range) |
−1.0 (−4.7–1.4) |
| Small for gestational age, n (%) |
19 (20) |
| Male, n (%) |
54 (58) |
| Apgar at 5 min, mean (range) |
6.4 (1–10) |
| Infants from multiple pregnancy, n (%) |
36 (39) |
| Antenatal corticosteroids, n (%) |
91 (98) |
| Caesarean section, n (%) |
58 (62) |
| Maternal smoking, n (%) |
8 (9) |
| Preeclampsia, n (%) |
9 (10) |
| Chorioamnionitis, n (%) |
19 (20) |
| Preterm premature rupture of membranes, n (%) |
27 (29) |
| Maternal antibiotics, n (%) |
55 (59) |
| Inclusion site, Stockholm/Linköping, n/n (%/%) |
61/32 (66/34) |
| Antibiotics during first week, n (%) |
92 (99) |
| Antibiotics during second week, n (%) |
77 (83) |
| Days on antibiotics, mean (range) |
28.8 (4–64) |
| Days on mechanical ventilation, mean (range) |
20.8 (0–75) |
| Sepsis, culture proven, n (%) |
35 (38) |
| NEC, Bell stage II–III, n (%) |
11 (12) |
