Local anesthetic agents--pharmacologic basis for use in obstetrics: a review.

Because of the minimal effects on mother and fetus, regional anesthetic technics are widely employed for labor and delivery. However, the literature describes at least 35 fetal and neonatal deaths and a frightening incidence of fetal distress associated with paracervical block for 1st-stage labor. Continuous lumbar epidural anesthesia for 1st-stage labor has also been associated with fetal distress, but this is minimal and no deaths have been reported. Bupivacaine, a relatively new, long-lasting local anesthetic, is extemely toxic when administered paracervically, but no deaths have been reported with its use for epidural anesthesia. While choice of method and agent must be individualized, continuous lumbar epidural block with bupivacaine appears as effective as and less often dangerous to the fetus than paracervical block.