Fetal heart rate abnormalities after regional analgesia for labor pain: The effect of intrathecal opioids

BACKGROUND AND OBJECTIVES: Intrathecal opioids used to relieve labor pain have been associated with uterine hyperactivity and nonreassuring fetal heart rate abnormalities. We retrospectively evaluated all charts of singleton, term, vertex-presenting parturients in active labor requesting neuraxial pain relief during a 1-year period for the occurrence of nonreassuring fetal heart rate tracings. METHODS: Three different strategies to relieve labor pain were routinely used in our department: conventional epidural using 10 mL bupivacaine 0.125% and sufentanil 0.75 microg/mL; combined spinal and epidural (CSE) using intrathecal sufentanil (7.5 microg); and CSE using intrathecal bupivacaine (2.5 mg) and sufentanil (1.5 microg). Charts (n = 1,293) were evaluated for nonreassuring fetal heart tracings and uterine hyperactivity as well as for neonatal and labor outcome. RESULTS: Intrathecal sufentanil (7.5 microg) produced significantly more nonreassuring tracings and uterine hyperactivity. However, this did not result in more cesarean deliveries or detrimental neonatal outcome. CONCLUSION: Based on this retrospective analysis, we conclude that intrathecal sufentanil in a dose of 7.5 microg has the potential to result in more nonreassuring fetal heart rate tracings compared with both intrathecal analgesia using a bupivacaine (2.5 mg)/sufentanil (1.5 microg) mixture and epidural analgesia using bupivacaine, sufentanil, and epinephrine. Reg Anesth Pain Med 2001;26:257-262.