Table 2.
Perinatal, maternal and labour outcomes.
| Preference for induction of labour ≤ 411/7 (n = 372) |
Preference for expectant management (n = 2174) |
Unadjusted RR (95 % CI) |
Adjusted RR (95 % CI)‡‡ |
|
|---|---|---|---|---|
| Composite adverse perinatal outcome* | 4 (1.1 %) | 42 (1.9 %) | 0.56 (0.20–1.54) | 0.56 (0.17–1.79) |
| Severe adverse perinatal outcome† (with Apgar score 5′< 4 instead of < 7) |
1 (0.3 %) | 22 (1.0 %) | 0.27 (0.04–1.97) | 0.39 (0.05–2.88) |
| Stillbirth | 0 | 0 | N/A | N/A |
| Neonatal death, post-partum†† | 0 | 0 | N/A | N/A |
| Apgar score 5 min post-partum | ||||
| < 7 | 3 (0.8 %) | 35 (1.6 %) | 0.50 (0.16–1.62) | 0.43 (0.10–1.78) |
| < 4 | 0 | 7 (0.3 %) | N/A | N/A |
| Admission neonate to | ||||
| Intensive Care (NICU) | 1 (0.3 %) | 18 (0.8 %) | 0.33 (0.04–2.43) | 0.51 (0.07–3.85) |
| Medium Care | 25 (6.7 %) | 143 (6.6 %) | 1.02 (0.68–1.54) | 0.97 (0.62–1.52) |
| Meconium aspiration syndrome | 0 | 6 (0.3 %) | N/A | N/A |
| Plexus brachialis injury | 0 | 0 | N/A | N/A |
| Congenital abnormality | 1 (0.3 %) | 9 (0.4 %) | 0.65 (0.08–5.11) | 0.72 (0.09–5.76) |
| Hypoglycaemia | 3 (0.8 %) | 13 (0.6 %) | 1.35 (0.39–4.71) | 1.67 (0.48–5.83) |
| Neonatal infection / sepsis | 6 (1.6 %) | 76 (3.5 %) | 0.46 (0.20–1.05) | 0.39 (0.14–1.05) |
| Neonatal sex, female | 180 (48.5 %) | 1078 (49.7 %) | 0.98 (0.87–1.09) | 0.96 (0.85–1.09) |
| Birthweight (g), mean (SD) | 3774 (418) | 3742 (424) | – | – |
| Small of gestational age (< 2.3rd percentile) | 6 (1.6 %) | 33 (1.5 %) | 1.06 (0.45–2.52) | 1.24 (0.52–2.92) |
| Large for gestational age (> 97.7th percentile) | 13 (3.5 %) | 43 (2.0 %) | 1.77 (0.96–3.25) | 1.69 (0.85–3.35) |
| Gestational age onset of labour (weeks+days), median (IQR) |
410/7 (406/7-411/7) | 412/7 (410/7-414/7) | – | – |
| Onset of labour | ||||
| Spontaneous | 154 (41.4 %) | 1879 (86.4 %) | 0.48 (0.42–0.54) | 0.25 (0.22–0.29) |
| Induction | 217 (58.3 %) | 292 (13.4 %) | 4.34 (3.79–4.98) | 4.02 (3.47–4.66) |
| Fetal condition | 19/217 (8.8 %) | 83/292 (28.4 %) | – | – |
| Maternal condition | 11/217 (5.1 %) | 27/292 (9.2 %) | – | – |
| > 24 h ruptured membranes | 0 | 5/292 (1.7 %) | – | – |
| Postterm pregnancy (≥ 420/7 weeks) | 0 | 177/292 (60.6 %) | – | – |
| Maternal preference | 187/217 (86.2 %) | 0 | N/A | N/A |
| Planned caesarean section | 1 (0.3 %) | 3 (0.1 %) | 1.95 (0.20–18.68) | 1.90 (0.20–18.52) |
| Mode of delivery | ||||
| Spontaneous vaginal delivery | 292 (78.5 %) | 1708 (78.6 %) | 1.00 (0.94–1.06) | 0.88 (0.73–1.07) |
| Operative vaginal delivery | 41 (11.0 %) | 273 (12.6 %) | 0.88 (0.64–1.20) | 0.99 (0.73–1.35) |
| Caesarean section (planned and secondary) | 39 (10.5 %) | 193 (8.9 %) | 1.18 (0.85–1.64) | 1.32 (0.95–1.84) |
| Composite adverse maternal outcome‡ | 43 (11.6 %) | 248 (11.4 %) | 1.01 (0.75–1.37) | 0.99 (0.71–1.39) |
| Maternal death†† | 0 | 0 | N/A | N/A |
| Postpartum blood loss (mL), median (IQR)§ | 300 (200–500) | 300 (200–500) | – | – |
| Haemorrhage postpartum ≥ 1000 mL | 30 (8.1 %) | 183 (8.4 %) | 0.96 (0.66–1.39) | 0.83 (0.54–1.27) |
| Haemorrhage postpartum ≥ 2000 mL | 7 (1.9 %) | 50 (2.3 %) | 0.82 (0.37–1.79) | 0.72 (0.29–1.79) |
| Manual removal of placenta¶ (vaginal birth only) |
9/333 (2.7 %) | 69/1981 (3.5 %) | 0.78 (0.40–1.55) | 0.77 (0.36–1.66) |
| Obstetrical anal sphincter injuries (OASIS)¶ | 11/333 (3.3 %) | 73/1981 (3.7 %) | 0.90 (0.48–1.67) | 1.16 (0.62–2.18) |
| Maternal admission to Intensive Care Unit (highest level of care) |
0 | 2 (0.1 %) | N/A | N/A |
*Defined as perinatal death and/or 5 min Apgar score < 7 and/or NICU admission and/or meconium aspiration syndrome and/or plexus brachialis injury.
†Defined as Composite adverse perinatal outcome, tough where 5 min. Apgar score < 4 instead of < 7.
‡Defined as haemorrhage postpartum ≥ 1000 mL, and/or manual removal of placenta, and/or 3rd or 4th degree tears (OASIS), and/or intensive care admission, and/or maternal death.
§Of postpartum blood loss 65 cases are missing.
¶Manual removal of placenta and OASIS of vaginal deliveries only.
††One neonatal death and one maternal death occurred in the undefined preference or management strategy group.
‡‡Adjusted for ethnicity, SES, parity and BMI. BMI dichotomised as obese (BMI ≥ 25 or < 25).
SD: standard deviation; IQR: interquartile range