Paracervical block--a viable alternative for labor pain relief?

Two hundred and forty-eight consecutive deliveries with a 0.25% bupivacaine paracervical block (PCB) using a superficial injection technique were studied prospectively during the progress of labor in the three month study period. Parturients with signs of fetal distress were excluded. Pain level and the maternal, fetal and neonatal effects related to PCB were evaluated.

Pain intensity level was assessed on a visual scoring scale (0-10). The intrapartum fetal heart rate patterns were recorded and reviewed to correlate the incidence of paracervical fetal bradycardia.

Parturients with PCB were provided a significant reduction (p < 0.001) in pain levels and the change in pain scores could be maintained until the beginning of the second stage. After the block, bradycardia patterns were noted in five (2.0%) fetuses, a fetal heart rate ranged from 60 to 105 beats per minute with an onset time of 2-20 minutes after the block and a duration of 4-12 minutes. All newborns in the bradycardia group were delivered vaginally without signs of asphyxia.

PCB in selected parturients with a low-dose superficial technique has been shown to be an effective analgesic modality with minimal fetal and neonatal side-effects, but post-blockade fetal bradycardia cannot be wholly eliminated.