Cases* | Controls* | Odds ratio (95% CI) | p Value | |
Age | ||||
<20 years | 6 (4.4) | 6 (2.0) | 0.12 | |
⩾20 years | 131 | 296 | 0.45 (0.15 to 1.41) | |
Ethnic group | ||||
White | 98 (82.4) | 204 (81.9) | 0.9 | |
Black | 9 (7.6) | 19 (7.6) | 0.88 (0.36 to 2.17) | |
Indian | 4 | 8 | 0.76 (0.19 to 3.04) | |
Pakistani | 1 | 3 | 0.98 (0.09 to 10.85) | |
Bangladeshi | 1 | 2 | 1.94 (0.12 to 31.24) | |
Chinese | 0 | 1 | 0.00 (0.00 to ∞) | |
Other | 6 | 12 | 1.11 (0.38 to 3.23) | |
Marital status | ||||
Married/stable relationship | 100 (72.9) | 236 (79.2) | 0.5 | |
Divorced | 1 | 2 | 1.30 (0.11 to 14.70) | |
Single | 36 | 59 | 1.39 (0.85 to 2.28) | |
Widowed | 0 | 1 | 0.00 (0.00 to ∞) | |
Antenatal attendance | ||||
Yes | 136 | 298 | ∞ (0.00 to ∞) | 0.24 |
No | 0 | 2 | ||
No of previous pregnancies | ||||
0 | 62 (45.3) | 103 (34.1) | 0.83 per pregnancy (0.70 to 0.98) | 0.027 |
⩾1 | 75 | 199 | ||
No of live born | ||||
0 | 86 (62.8) | 152 (50.3) | 0.77 per live born (0.61 to 0.97) | 0.019 |
⩾1 | 51 | 150 | ||
Multiple pregnancy | ||||
Yes | 11 (8.0) | 22 (7.3) | 1.63 (0.63 to 4.19) | 0.3 |
No | 126 | 280 | ||
GBS bacteruria | ||||
Yes | 8 (5.9) | 3 (1) | 5.55 (1.47 to 20.96) | 0.006 |
No | 127 | 297 | ||
GBS carrier | ||||
Yes | 33 (24.4) | 11 (3.7) | 8.47 (3.73 to 19.27) | <0.001 |
No | 102 | 289 | ||
Previous baby with GBS | ||||
Yes | 0 | 2 | 0.00 (0.00 to ∞) | 0.14 |
No | 135 | 299 | ||
Previous fetal death | ||||
Yes | 29 (21.5) | 81 (26.9) | 0.74 (0.45 to 1.23) | 0.25 |
No | 106 | 220 | ||
Epidural in labour | ||||
Yes | 84 (62.7) | 140 (46.7) | 2.15 (1.35 to 3.43) | <0.001 |
No | 50 | 160 | ||
Maternal temperature >38°C | ||||
Yes | 15 (11.3) | 5 (1.7) | 5.62 (2.03 to 15.55) | <0.001 |
No | 118 | 295 | ||
Maximum intrapartum temperature | 2.44 per °C (1.66 to 3.59) | <0.001 | ||
Duration of ruptured membranes | ||||
<18 h | 83 | 240 | ||
⩾18 h | 53 (39.0) | 60 (20.0) | 2.69 (1.67 to 4.34) | <0.001 |
Duration of ruptured membranes | ||||
<24 h | 95 | 255 | ||
⩾24 h | 41 (30.1) | 45 (15.0) | 2.37 (1.42 to 3.93) | <0.001 |
Antibiotics in labour | ||||
Yes | 15 (11.0) | 28 (9.3) | 1.04 (0.51 to 2.10) | 0.9 |
No | 119 | 273 | ||
Mode of delivery | ||||
Normal vaginal delivery | 54 (39.7) | 159 (53.2) | <0.001 | |
Elective caesarean section | 7 (5.2) | 39 (13) | 0.49 (0.19 to 1.27) | |
Emergency intervention† | 75 (55.1) | 101 (33.8) | 2.30 (1.42 to 3.62) | |
No of vaginal examinations | ||||
0 | 20 | 72 | 1.13 per examination (1.03 to 1.23) | 0.011 |
⩾1 | 117 (85.4) | 230 (76.2) | ||
Fetal tachycardia >160 beats per minute | ||||
Yes | 51 (39.2) | 53 (17.9) | 2.81 (1.68 to 4.69) | <0.001 |
No | 79 | 244 | ||
Cardiotocographic evidence of fetal distress‡ | ||||
Yes | 32 (32) | 41 (13.8) | 2.40 (1.32 to 4.37) | 0.004 |
No | 100 | 256 | ||
Fetal scalp electrodes | ||||
Yes | 5 (3.8) | 6 (2.0) | 1.68 (0.51 to 5.57) | 0.4 |
No | 125 | 291 | ||
Fetal blood sampling | ||||
Yes | 8 (6.2) | 3 (1.0) | 5.33 (1.41 to 20.10) | 0.008 |
No | 122 | 294 | ||
Maternal infection§ | ||||
Yes | 14 (10.4) | 9 (3.0) | 4.78 (1.81 to 12.66) | <0.001 |
No | 121 | 293 | ||
Postdelivery antibiotics for mother | ||||
Yes | 54 (40.3) | 83 (27.6) | 1.86 (1.15 to 3.01) | 0.011 |
No | 80 | 218 |
*Number (%). Numbers do not always add up to the same total due to missing data in case notes.
†Ventouse, forceps or emergency cesarean section.
‡Early deceleration, late variable deceleration, complicated tachycardia, bradycardia.
§Infection mentioned in notes, for example urinary-tract infection, endometritis.
GBS, Group B streptococcus.