Demographic and clinical variables of infants with moderate or severe hypoxic-ischaemic encephalopathy born in level 2 centres post propensity score-matching
| Variables | Unmatched infants | Propensity score matched infants | ||||||
| Born in non-CC | Born in CC | SMD | P value† | Born in non-CC | Born in CC | SMD | P value† | |
| n=1546* | n=701* | n=696* | n=696* | |||||
| Gender (male) | 877 (56.7) | 373 (53.2) | −0.07 | 0.12 | 366 (52.6) | 373 (53.6) | 0.02 | 0.71 |
| Birth weight (g) | 3332 (2929–3760) | 3370 (2960–3730) | −0.033 | 0.42 | 3372 (3004–3764) | 3370 (2953–3730) | 0.036 | 0.5 |
| Gestation (weeks) | 40 (38–41) | 40 (38–41) | −0.047 | 0.28 | 40 (39–41) | 40 (38–41) | 0.032 | 0.56 |
| Birth year | 2014 (2012–2015) | 2014 (2012–2015) | −0.134 | 0.003 | 2014 (2013–2015) | 2014 (2012–2015) | 0.01 | 0.86 |
| Pre-eclampsia | 71 (4.6) | 38 (5.4) | −0.04 | 0.4 | 31 (4.5) | 38 (5.5) | −0.046 | 0.39 |
| Maternal Infection | 383 (24.8) | 173 (24.7) | 0.002 | 0.96 | 176 (25.3) | 172 (24.7) | 0.013 | 0.8 |
| Mode of delivery‡: | ||||||||
| Em CS no labour | 263 (17.0) | 118 (16.8) | 0.005 | 0.92 | 115 (16.5) | 118 (17.0) | −0.012 | 0.83 |
| Em CS in labour | 494 (32.0) | 205 (29.2) | 0.059 | 0.2 | 200 (28.7) | 205 (29.5) | −0.016 | 0.77 |
| El CS no labour | 13 (0.8) | 7 (1.0) | −0.017 | 0.71 | 7 (1.0) | 6 (0.9) | 0.015 | 0.78 |
| El CS in labour | 6 (0.4) | 3 (0.4) | −0.006 | 0.89 | 4 (0.6) | 3 (0.4) | 0.02 | 0.71 |
| Instrumental | 240 (15.5) | 144 (20.5) | −0.131 | 0.003 | 137 (19.7) | 140 (20.1) | −0.011 | 0.84 |
| Missing | 57 (3.7) | 19 (2.7) | 0.055 | 0.24 | 28 (4.0) | 19 (2.7) | 0.072 | 0.18 |
| Presentation: | ||||||||
| Cephalic | 1231 (79.6) | 586 (83.6) | −0.103 | 0.03 | 588 (84.5) | 582 (83.6) | 0.024 | 0.66 |
| Breech | 84 (5.4) | 42 (6.0) | −0.024 | 0.59 | 34 (4.9) | 41 (5.9) | −0.044 | 0.41 |
| Transverse lie | 10 (0.7) | 4 (0.6) | 0.01 | 0.83 | 4 (0.6) | 4 (0.6) | 0 | 1 |
| Other | 11 (0.7) | 5 (0.7) | 0 | 1 | 3 (0.4) | 5 (0.7) | −0.038 | 0.48 |
| Missing | 210 (13.6) | 64 (9.1) | 0.141 | 0.003 | 67 (9.6) | 64 (9.2) | 0.015 | 0.78 |
| Intra-partum events | 187 (12.1) | 89 (12.7) | −0.018 | 0.69 | 93 (13.4) | 89 (12.8) | 0.017 | 0.75 |
| Significant resuscitation | 935 (60.50 | 434 (61.9) | −0.029 | 0.52 | 440 (63.2) | 432 (62.1) | 0.023 | 0.66 |
| Apgar at 5 min | 4 (2–5) | 4 (2–6) | −0.07 | 0.09 | 4 (3–6) | 4 (2–6) | 0.018 | 0.74 |
| Grade of HIE | ||||||||
| Grade 2 | 521 (33.7) | 243 (34.7) | 0.02 | 0.66 | 236 (33.9) | 240 (34.5) | 0.012 | 0.82 |
| Grade 3 | 1025 (66.3) | 458 (65.3) | 460 (66.1) | 456 (65.5) | ||||
*Data are n (%) or median (interquartile).
†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 − normal vaginal delivery.
CC, cooling centre; El CS, elective caesarean section; Em CS, emergency caesarean section; HIE, hypoxic-ischaemic encephalopathy; NVD, normal vaginal delivery; SMD, standardised mean difference.