Use of epidural analgesia and its relation to caesarean and instrumental deliveries - a population-based study of 94,217 primiparae

Objectives: To investigate the association between epidural analgesia for labour-pain relief and mode of delivery. Study design: The Swedish medical birth register covers 99% of all births and contains prospectively collected information from all delivery units in Sweden. The present population-based cohort study includes singleton births among nulliparae during 1998-2000, excluding deliveries with elective caesarean section, giving study population of n = 94,217. The frequencies of epidural block in this population were estimated for each delivery unit. The outcomes studied were non-elective caesarean section and instrumental delivery. Results: There was no clear association between frequency of epidural block and caesarean section and instrumental delivery, respectively. Delivery units with the lowest (20-29%) and the highest (60-64%) relative frequencies of epidural block had the lowest proportion of caesarean section (9. 1 %). For the other groups the proportion varied between 10.3 and 10.6%. Instrumental deliveries were most common, 18.8%, in delivery units with 50-59% frequency of epidural block use. The lowest incidence (14. 1 %) was in units using epidurals in 30-39% of cases. In the other groups (20-29, 40-49 and 60-64%) the proportion varied between 15.3 and 15.7%. Conclusions: This investigation shows no clear association between epidural use and caesarean section or instrumental delivery, indicating that there is no reason to restrict the epidural rate to improve obstetric outcome. (C) 2005 Published by Elsevier Ireland Ltd.