Cerebral palsy by antenatal and peripartum risk factors
| Risk factor | ⩽32 weeks | 33–36 weeks | ⩾37 weeks | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Cases | Controls | OR* (95% CI) | Cases | Controls | OR* (95% CI) | Cases | Controls | OR* (95% CI) | |
| Values are number (%). Numbers do not always add up to totals because of missing values. | |||||||||
| *OR (odds ratio) adjusted for source of data. | |||||||||
| †When 0 in cell, unadjusted OR calculated after adding 0.5 to each cell.15 | |||||||||
| – Indicates that OR cannot be calculated. | |||||||||
| CI, Confidence interval; SGA, small for gestational age. | |||||||||
| Number of subjects | 73 | 286 | 36 | 70 | 126 | 290 | |||
| Antenatal | |||||||||
| Parity | |||||||||
| 0 | 34 (47) | 137 (48) | 1 | 22 (61) | 30 (43) | 1 | 66 (52) | 141 (49) | 1 |
| 1 | 20 (27) | 77 (27) | 1.0 (0.6 to 1.9) | 6 (17) | 25 (36) | 0.3 (0.1 to 0.9) | 35 (28) | 86 (30) | 0.9 (0.5 to 1.4) |
| 2 | 9 (12) | 47 (16) | 0.7 (0.3 to 1.6) | 7 (19) | 7 (10) | 1.4 (0.4 to 4.5) | 15 (12) | 46 (16) | 0.7 (0.6 to 1.1) |
| 3+ | 10 (14) | 25 (9) | 1.5 (0.7 to 3.5) | 1 (3) | 8 (11) | 0.2 (<0.1 to 1.5) | 10 (8) | 17 (6) | 1.3 (0.6 to 2.9) |
| Socioeconomic class | |||||||||
| I–III | 51 (76) | 191 (70) | 1 | 27 (82) | 56 (85) | 1 | 83 (79) | 201 (78) | 1 |
| IV–VI | 16 (24) | 81 (30) | 0.8 (0.4 to 1.5) | 6 (18) | 10 (15) | 1.2 (0.2 to 6.6) | 22 (21) | 57 (20) | 0.9 (0.5 to 1.6) |
| Pre-eclampsia | |||||||||
| No | 65 (90) | 223 (78) | 1 | 26 (77) | 54 (78) | 1 | 109 (86) | 281 (97) | 1 |
| Yes | 7 (10) | 62 (22) | 0.4 (0.2 to 1.0) | 8 (23) | 15 (22) | 1.1 (0.4 to 2.9) | 17 (14) | 9 (3) | 5.1 (2.2 to 12.0) |
| SGA >1SD below mean | |||||||||
| No | 67 (92) | 180 (64) | 1 | 21 (58) | 41 (59) | 1 | 89 (72) | 243 (84) | 1 |
| Yes | 6 (8) | 103 (36) | 0.2 (0.1 to 0.4) | 15 (42) | 29 (41) | 1.0 (0.4 to 2.3) | 34 (28) | 45 (16) | 2.1 (1.2 to 3.4) |
| Peripartum | |||||||||
| Placental abruption | |||||||||
| No | 46 (66) | 219 (77) | 1 | 32 (94) | 65 (93) | 1 | 116 (94) | 284 (98) | 1 |
| Yes | 24 (34) | 64 (23) | 1.7 (1.0 to 3.0) | 2 (6) | 5 (7) | 0.8 (0.2 to 4.4) | 8 (6) | 6 (2) | 3.3 (1.1 to 10.0) |
| Prelabour rupture of membranes | |||||||||
| No | 41 (58) | 206 (72) | 1 | 22 (65) | 47 (67) | 1 | 114 (92) | 264 (91) | 1 |
| Yes | 30 (42) | 80 (28) | 1.8 (1.0 to 3.0) | 12 (35) | 23 (33) | 1.1 (0.5 to 2.6) | 10 (8) | 25 (9) | 1.0 (0.5 to 2.2) |
| Chorioamnionitis | |||||||||
| No | 59 (83) | 271 (95) | 1 | 31 (91) | 69 (99) | 1 | 123 (99) | 290 (100) | – |
| Yes | 12 (17) | 15 (5) | 3.0 (1.3 to 7.0) | 3 (9) | 1 (1) | 6.7 (0.7 to 66.7) | 1 (1) | 0 (0) | |
| Intrapartum pyrexia | |||||||||
| No | 61 (86) | 258 (92) | 1 | 33 (97) | 69 (99) | 1 | 118 (96) | 286 (100) | 1 |
| Yes | 10 (14) | 23 (8) | 1.7 (0.8 to 3.9) | 1 (3) | 1 (1) | 2.1 (0.1 to 34.5) | 5 (4) | 1 (0.3) | 13.1 (1.5 to 114.3) |
| Intrapartum hypoxia | |||||||||
| No | 70 (96) | 285 (100) | 1 | 33 (92) | 70 (100) | 1 | 101 (80) | 290 (0) | 1 |
| Yes | 3 (4) | 1 (0.3) | 12.2 (1.2 to 119) | 3 (8) | 0 (0) | 14.7† (0.8 to 298.5) | 25 (20) | 0 | 146.0† (7.4 to 3651) |
| Onset of labour | |||||||||
| Spontaneous | 55 (76) | 168 (59) | 1 | 15 (42) | 41 (59) | 1 | 68 (54) | 208 (72) | 1 |
| Induction | 5 (7) | 4 (1) | 2.7 (0.7 to 11.0) | 10 (28) | 14 (20) | 2.0 (0.7 to 5.3) | 48 (38) | 70 (24) | 2.1 (1.3 to 3.3) |
| Caesarean | 12 (17) | 114 (40) | 0.3 (0.2 to 0.7) | 11 (31) | 15 (21) | 2.0 (0.8 to 5.3) | 10 (8) | 12 (4) | 2.6 (1.1 to 6.3) |
| Neonatal | |||||||||
| Neonatal sepsis | |||||||||
| No | 41 (57) | 228 (81) | 1 | 23 (72) | 60 (90) | 1 | 111 (93) | 277 (99) | 1 |
| Yes | 31 (43) | 53 (19) | 3.1 (1.8 to 5.4) | 9 (28) | 7 (10) | 3.3 (1.1 to 10.1) | 8 (7) | 2 (1) | 10.6 (2.1 to 51.9) |
| Combined markers of infection | |||||||||
| Chorioamnionitis or intrapartum pyrexia or neonatal sepsis | |||||||||
| No | 33 (47) | 203 (73) | 1 | 20 (67) | 58 (87) | 1 | 106 (91) | 274 (99) | 1 |
| Yes | 37 (53) | 75 (27) | 2.8 (1.6 to 4.9) | 10 (33) | 9 (13) | 3.2 (1.1 to 9.1) | 11 (9) | 3 (1) | 10.3 (2.7 to 38.7) |