Results
The score comprised seven variables significantly associated with failed
mid-cavity VAD: head-perineum distance ≥51 mm (p<0.001), bulky
caput succedaneum (p<0.001), maternal height ≤1.54 m
(p<0.001), duration of expulsive efforts before vacuum
<21 minutes or >30 minutes (p=0.0013), duration
from five centimetres to complete cervical dilation ≥3 hours (p=0.0091),
term ≥42 weeks of gestation (p=0.032), and occiput-posterior or
occiput-transverse fetal head position (p=0.041). The model was reliable
(Hosmer-Lemeshow test =8.5; p=0.39) and accurate (concordance index
=0.74). The threshold for a transfer to the operating theatre was set at
16.3 %. Advanced preparation of caesarean section equipment and
anticipated extension of epidural analgesia were significantly
associated with a decrease in the delay between VAD failure and birth by
caesarean section (p<0.001).