Table 1

Demographic and clinical variables of infants ≥36 weeks gestational age with moderate or severe hypoxic-ischaemic encephalopathy both prepropensity and postpropensity score-matching

VariablesUnmatched infantsPropensity score-matched infants
Born in non-CCBorn in CCSMDP value†Born in non-CCBorn in CCSMDP value†
n=2364*n=2695*n=2165*n=2165*
Gender (male)1354 (57.3)1417 (52.6)−0.0950.0021203 (55.6)1225 (56.6)0.020.49
Birth weight (g)3340 (2957–3760)3332 (2940–3750)0.0140.73340 (2944–3760)3340 (2970–3775)−0.0180.23
Gestation (weeks)40 (38–41)40 (38–41)−0.0150.4740 (38–41)40 (38–41)−0.0060.85
Birth year2014 (2012–2015)2014 (2012–2015)−0.0890.022014 (2012–2015)2014 (2012–2015)0.0260.4
Pre-eclampsia113 (4.8)120 (4.5)0.0160.5898 (4.5)97 (4.5)0.0030.92
Maternal infection555 (23.5)559 (20.7)0.0660.02480 (22.2)480 (22.2)00.99
Mode of delivery‡
 Em CS no labour405 (17.1)449 (16.7)0.0130.66375 (17.3)357 (16.5)0.0220.48
 Em CS in labour682 (28.9)787 (29.2)−0.0080.78639 (29.5)630 (29.1)0.0080.8
 El CS no labour20 (0.9)28 (1.0)−0.020.4821 (0.95)18 (0.81)0.0140.64
 El CS in labour7 (0.3)6 (0.2)0.0140.617 (0.33)6 (0.27)0.0110.72
 Instrumental358 (15.1)514 (19.1)−0.104<0.001355 (16.4)310 (14.3)0.060.05
 Missing100 (4.2)84 (3.1)0.0590.0480 (3.7)74 (3.4)0.0140.65
Presentation
 Cephalic1833 (77.5)2206 (81.9)−0.107<0.0011753 (81.0)1734 (80.1)0.0220.47
 Breech154 (6.5)205 (7.6)−0.0430.13142 (6.6)162 (7.5)−0.0360.2
 Transverse11 (0.5)12 (0.5)0.0030.9111 (0.62)11 (0.5)0.0030.92
 Other20 (0.9)17 (0.6)0.0250.3715 (0.7)15 (0.68)0.0040.9
 Missing346 (14.6)255 (9.5)0.16<0.001244 (11.3)244 (11.3)01
Intrapartum events276 (11.7)349 (13.0)−0.0390.17265 (12.2)257 (11.9)0.0110.72
Significant resuscitation1364 (57.7)1703 (63.2)−0.112<0.0011312 (60.6)1278 (59.0)0.0330.28
Apgar at 5 min4 (2–5)4 (2–6)−0.010.564 (2–5)4 (2–6)−0.0030.72
Grade of HIE
 Grade 2811 (34.3)1068 (39.6)0.11<0.001779 (36.0)760 (35.1)−0.0180.55
 Grade 31553 (65.7)1627 (60.4)1386 (64.0)1405 (64.9)
Place of birth level§
 Level 1670 (28.3)0615 (28.4)0
 Level 21546 (65.4)701 (26.0)0.861<0.0011425 (65.8)566 (26.2)0.868<0.001
 Level 318 (0.8)1938 (71.9)−2.198<0.00116 (0.8)1551 (71.6)−2.183<0.001
 Home96 (4.1)56 (2.1)0.094<0.00182 (3.8)48 (2.2)0.0940.002
 Midwife led unit34 (1.4)027 (1.2)0
Interhospital transfers§
 L1–L3 transfer632 (26.7)00.854<0.001578 (26.7)0<0.001
 L2–L3 transfer1386 (58.6)452 (16.8)0.957<0.0011283 (59.3)358 (16.5)0.981<0.001
  • *Data are n (%) or median (IQR).

  • †Categorical data analysed using χ² test; non normally distributed continuous data analysed using Mann-Whitney U test; matched data by paired t-test for continuous data or McNemar’s test or extensions thereof for binary and categorical data.

  • ‡Compared with baseline – NVD.

  • §Variables not included in propensity score matching.

  • CC, cooling centre; El CS, elective caesarean section; Em CS, emergency caesarean section; HIE, hypoxic-ischaemic encephalopathy; L2, level 2; L3, Level 3; NVD, normal vaginal delivery; SMD, Standardised mean difference.