Objective: To investigate whether changes in maternal and birth characteristics explain the increase in the use of epidural analgesia during labor. Methods: Using data from a statewide surveillance system of all births, the study included 857 667 women who labored at term between 1992 and 2003 in New South Wales, Australia. Annual rates of epidural analgesia use were calculated. Logistic regression models were used to predict epidural analgesia rates over time, and were compared with observed rates. Results: Epidural analgesia use increased from 17.2% in 1992 to 26.5% in 2003. The increase in the proportion of women with factors associated with epidural analgesia use explained almost half of the increase in rate. After controlling for these factors, the odds of a woman receiving epidural analgesia in 2003 compared with 1992 were 1.42 (95% CI, 1.38–1.46). Conclusion: Changes in maternal or birth characteristics partially explain the increase in epidural analgesia rate. The unexplained increase may be due to increased availability or other factors.
International Journal of Gynecology & Obstetrics Vol. 102, Issue 3, p. 253-258