The incidence of fetal heart rate changes after intrathecal fentanyl laboranalgesia

We performed a retrospective review to compare the incidence of new fetal h eart rate abnormalities after institution of either intrathecal fentanyl or conventional epidural labor analgesia. In chronological order, the first 1 00 parturients in active labor who had received epidural analgesia and had recorded fetal heart rate (FHR) traces for 30 min before and after injectio n were identified, as were the first 100 parturients who had received intra thecal fentanyl analgesia. A perinatologist blinded to the anesthetic techn ique evaluated each recording and identified any changes in the FHR between the before and after tracings. The incidence of new "negative" (implying w orsened fetal status) changes was 6% in the epidural group and 12% in the i ntrathecal group (P > 0.05, not significant). There were no differences in incidence or degree of blood pressure change, need for cesarean delivery, n eonatal outcome, parity, or oxytocin use. No parturient required urgent or emergent cesarean delivery, and all changes resolved within the 30-min obse rvation period. A much larger study would be required to determine whether this six percentage point difference represents a true difference between g roups, and its clinical significance. Implications: We compared the inciden ce of fetal heart rate changes after two techniques of labor analgesia. Bot h techniques were associated with a low (6%-12%) incidence of changes, but a much larger series would be required to determine whether this represents a true difference. No difference in neonatal outcome was found.