A comparison of the effects of epidural and meperidine analgesia during labor on fetal heart rate

OBJECTIVE: To estimate the effects of initiation of epidural analgesia on fetal heart rate (FHR) patterns compared with intravenous meperidine analgesia. METHODS: Fetal heart rate patterns in 200 nulliparous women with term pregnancies randomized to epidural analgesia with 0.25% bupivacaine were compared with those of 156 similar women given intravenous meperidine. Fetal heart rate patterns occurring within 40 minutes of initiation of labor analgesia were retrospectively read by three maternal-fetal medicine specialists who were blind to clinical events, including type of labor analgesia. RESULTS: Meperidine, compared with epidural analgesia, was associated with statistically significantly less beat-to-beat variability (absent or less than 5 beats per minute) of the FHR (30% versus 7% of fetuses, P <.001) in the first 40 minutes after initiation of analgesia, as well as with fewer FHR accelerations (88% versus 62% of fetuses, P <.001). Neither the incidence of FHR decelerations nor the type of deceleration were significantly different between methods of labor analgesia. Specifically, 41% of women given meperidine exhibited FHR decelerations within 40 minutes, compared with 34% given epidural analgesia (P =.353). CONCLUSION: Epidural analgesia does not have deleterious effects on FHR.