Fetal heart rate variability after epidural fentanyl during labor

The effects of epidural fentanyl on fetal heart rate (FHR) were examined in 39 parturients, 19 given 75 micrograms epidural fentanyl and 20 given normal saline in 5-mL volumes administered randomly after establishment of adequate epidural lidocaine analgesia. Fetal heart rate was measured 15 min before and 15 min after lidocaine epidural analgesia, and for 60 min at 5-min intervals after administration of epidural fentanyl/placebo. A perinatologist blinded to the injected epidural solution analyzed FHR tracings. Epidural injections of fentanyl and saline, when given during established epidural lidocaine analgesia, were associated with equal reductions in FHR variability and the frequency of FHR accelerations (P less than 0.003). Neonatal outcome was also similar in both groups. The clinical significance, if any, of these moderate reductions in FHR during epidural lidocaine analgesia is unclear.