Labour characteristics in relation to time of operative vaginal delivery
| Daytime 08:00–19:59 n=301 (%) | Night-time 20:00–07:59 n=296 (%) | OR (95% CI) | |
|---|---|---|---|
| Induction of labour | 130 (43.2) | 167 (56.4) | 0.59 (0.43 to 0.81)* |
| First stage of labour >12 h | 20 (6.6) | 21 (7.1) | 0.93 (0.49 to 1.76) |
| Second stage of labour >2 h† | 164 (54.5) | 141 (47.6) | 1.32 (0.95 to 1.82) |
| Oxytocin in first stage of labour | 194 (64.5) | 193 (65.2) | 0.97 (0.69 to 1.35) |
| Oxytocin in second stage of labour | 225 (74.8) | 219 (74.0) | 1.04 (0.72 to 1.50) |
| Meconium stained liquor | 49 (16.3) | 40 (13.5) | 1.30 (0.86 to 1.95) |
| Pathological CTG (first stage) | 17 (5.6) | 16 (5.4) | 1.05 (0.52 to 2.11) |
| Pathological CTG (second stage) | 120 (39.9) | 114 (38.5) | 1.06 (0.76 to 1.47) |
| Fetal blood sample (FBS) performed | 79 (26.2) | 95 (32.1) | 0.75 (0.53 to 1.07) |
| Low pH <7.20 on FBS | 5 (1.7) | 4 (1.4) | 1.23 (0.33 to 4.64) |
| Regional analgesia (spinal/epidural) | 263 (87.4) | 264 (89.2) | 0.84 (0.51 to 1.38) |
| Local analgesia (pudendal/perineal) | 12 (4.0) | 15 (5.1) | 0.78 (0.36 to 1.69) |
| Fetal malposition (OP or OT)‡ | 36 (12.0) | 38 (12.8) | 0.92 (0.57 to 1.50) |
| Mid-cavity station (0/+1 cm) | 204 (67.8) | 205 (69.3) | 0.93 (0.66 to 1.32) |
| Caput succedaneum >+1§ | 67 (22.3) | 84 (28.4) | 0.72 (0.50 to 1.05) |
| Moulding >+1¶ | 9 (3.0) | 9 (3.0) | 0.98 (0.39 to 2.51) |
*p<0.05.
†Included the passive and active phases of the second stage of labour.
‡Occipito-posterior (OP) or occipito-transverse (OT).
§Caput succedaneum refers to the oedematous swelling formed on the presenting part of the fetal scalp during labour and is measured in centimetres.
¶Moulding refers to the change in shape of the fetal head as it adapts to the pelvic canal. It is classified as none when the fetal skull bones are normally separated, + when the bones touch, ++ when the bones overlap but separate easily with digital pressure and +++ when the bones overlap but are not separable with digital pressure.