Are women requiring unplanned intrapartum epidural analgesia different in a low-risk population?

We studied 645 full-term low-risk women in early labour in 6 units to evalu ate the effects of maternal characteristics and obstetric management in ear ly labour on the use of epidural analgesia, and to analyse the relationship between epidural analgesia, progress of labour and mode of delivery using multiple logistic regression. Among variables present in early labour, null iparity, ethnicity and obstetric unit were the strongest predictors of epid ural analgesia requirement. In nulliparous women, obstetric unit affected u se of epidural analgesia (P<0.05) and induction of labour was associated wi th increased use of epidural analgesia (odds ratio 3.45, 95% CI: 1.45-7.90) . In multiparous women, only ethnicity was statistically significant (P<0.0 5). Epidural analgesia was associated with longer labours and more instrume ntal deliveries (odds ratio 2.93, 95%-CI: 1.48-5.83). In the epidural group , however, we found a positive correlation between first stage duration and elapsed time before epidural analgesia. Furthermore rate of cervical dilat ion was similar in the non epidural group throughout the first stage (mean 3.41 cm/h, 95% CI: 3.19 3.63) and in the epidural group after epidural anal gesia decision (mean 3.99, 95% CI: 2.96 5.02), while the mean cervical dila tation rate before epidural analgesia was 0.88 cm/h (95% CI: 0.72-1.04), Th e need for epidural analgesia is, therefore, multifactorial and difficult t o predict. Whereas nulliparity increases epidural analgesia requirement, da ta on the progress of labour before pain relief suggest that epidural analg esia is a marker of pain severity and/or labour failure rather than the cau se of delayed progress in low-risk pregnancies.