Background: It has been argued that by adding an opioid to the local anesthetic drug used for epidural analgesia during childbirth, one can reduce the risk of operative delivery. Objective. In a population-based observational study, to evaluate the effect of adding an opioid to a local anesthetic drug on the risk of instrumental delivery or cesarean section.
Design: Comparison of delivery units adding/not adding opioid to the local anesthetic for epidural analgesia in labor.
Setting: All deliveries using epidural analgesia in Sweden during 1992-96 were evaluated on the basis of information stored at the Medical Birth Registry, the National Board of Health and Welfare, Stockholm.
Method: A questionnaire was sent to all delivery units (n=61), as well as to the Head of corresponding Anesthesiology Department in each hospital, requesting information regarding the period when opioids (sufentanil) were first added to the local epidural analgesic. Parturients given epidural analgesia were divided into three time-related groups: those delivered before the introduction of opioids (n=34,071), when opioids were first added (n=7,236), and since the introduction of opioids (n=44,384). Odds ratio (OR) with 95% confidence interval (CI) was used to assess the effect of sufentanil versus no sufentanil, on the risk of operative delivery. The parturients were stratified for year of delivery, age, and parity. Main outcome measures. Instrumental delivery, cesarean section, length of stay in hospital post partum.
Results: A significant reduction was observed in the incidence of instrumental delivery (OR 0.72; 95% CI 0.68-0.76). A similar though less pronounced effect was evident concerning the risk of cesarean section for nulliparae (OR 0.79; 95% CI 0.72-0.88) but not for multiparae (OR 0.93; 95% CI 0.80-1.07). Fewer women with an opioid added to the local anesthetic spent more than 4 (or more than 7) days in hospital post partum, compared with those given epidural analgesia without an opioid.
Conclusion: When added to the local anesthetic used for epidural analgesia, as in Sweden during the last 5 years, opioids appear to reduce the incidence of instrumental delivery and cesarean section and also the post partum hospital stay.