Total number
|
13,586
|
12,167
|
3427
| |
11,307
|
10,327
|
2701
| |
Infant and Perinatal Characteristics
|
Gestational age, mean(SD)
|
28.5(2.2)
|
28.3(2.2)
|
28.3(2.4)
|
<0.0001
|
28.3(2.6)
|
28.2(2.6)
|
27.9(2.7)
|
<0.0001
|
Birth weight, mean(SD)
|
1232 396)
|
1209 (387)
|
1234 (424)
|
<0.0001
|
1082 (274)
|
1068(267)
|
1055 (291)
|
<0.0001
|
Male sex
|
7345 (54.1)
|
6617 (54.5)
|
1838 (53.6)
|
0.6619
|
5762 (51.0)
|
5290(51.3)
|
1372 (50.8)
|
0.8571
|
Small for gestational age
|
1249 (9.2)
|
1133 (9.3)
|
317 (9.3)
|
0.9515
|
2369 (21.0)
|
2082(20.2)
|
521 (19.3)
|
0.0999
|
Singleton
|
9532 (70.2)
|
8417 (69.3)
|
2441 (71.3)
|
0.0478
|
7901 (69.9)
|
7099(68.8)
|
1930 (71.5)
|
0.016
|
Surfactant required
|
7336 (54.1)
|
7179 (59.0)
|
1941 (56.8)
|
<0.0001
|
6442 (57.1)
|
6233(60.4)
|
1649 (61.3)
|
<0.0001
|
Antenatal steroid use
|
12,902 (95.1)
|
10,156 (86.6)
|
3278 (95.7)
|
<0.0001
|
10,723 (95.0)
|
8520(85.7)
|
2581 (95.6)
|
<0.0001
|
Caesarean
|
8478 (62.7)
|
7117 (59.0)
|
2086 (61.2)
|
<0.0001
|
7311 (65.0)
|
6565(64.1)
|
1679 (62.7)
|
0.0613
|
Presentation (vertex)
|
8676 (65.4)
|
7307 (64.7)
|
2209 (65.7)
|
0.3872
|
7099 (64.2)
|
6004(63.0)
|
1720 (65.3)
|
0.0353
|
Maternal age, mean(SD)
|
29.8 (6.4)
|
30.5 (5.9)
|
29.9 (6.5)
|
<0.0001
|
29.7 (6.5)
|
30.5(6.0)
|
29.8 (6.6)
|
<0.0001
|
Neonatal Outcomes
|
Mortality
|
987 (7.3)
|
986 (8.1)
|
265 (7.7)
|
0.0407
|
948 (8.4)
|
945(9.2)
|
252 (9.3)
|
0.0841
|
Severe neurological injury
|
758 (5.6)
|
1409 (9.4)
|
220 (6.4)
|
<0.0001
|
711 (6.3)
|
1293(10.1)
|
202(7.5)
|
<0.0001
|
Severe retinopathy of prematurity
|
496 (3.7)
|
592 (4.9)
|
146 (4.3)
|
<0.0001
|
487 (4.3)
|
596(5.8)
|
144 (5.3)
|
<0.0001
|
Necrotising enterocolitis
|
591 (4.4)
|
690 (5.7)
|
143 (4.2)
|
<0.0001
|
566 (5.0)
|
641(6.2)
|
134 (5.0)
|
0.0002
|
Chronic lung disease
|
2381 (17.5)
|
2597 (21.3)
|
629 (18.4)
|
<0.0001
|
2233 (19.8)
|
2472(23.9)
|
586 (21.7)
|
<0.0001
|
Composite adverse outcome
|
3893 (28.7)
|
4564 (36.5)
|
1043 (30.4)
|
<0.0001
|
3649 (32.3)
|
4272(40.3)
|
962 (35.6)
|
<0.0001
|
Nosocomial Infection
|
2008 (14.8)
|
2188 (18.0)
|
484 (14.1)
|
<0.0001
|
1869 (16.5)
|
2069(20.0)
|
454 (16.8)
|
<0.0001
|