Analgesia and maternal side effects of pudendal block at delivery. A comparison of three local anesthetics.

In a randomized double-blind study, 1048 women received pudendal block (PDB) at vaginal delivery, using three different local anesthetics: mepivacaine 1% plain, mepivacaine 1% with epinephrine, and bupivacaine 0.25% plain. The PDB was given transvaginally in doses of 8 ml X 2. Mepivacaine - epinephrine was found to be more effective than the other local anesthetics. Loss of bearing down reflex after PDB was found in 31.2% of the mothers and most commonly when mepivacaine - epinephrine was used. Inhibition of labor was slightly more pronounced with mepivacaine - epinephrine. The different durations of the local anesthetics did not affect the analgetic effect in clinical use. It is concluded that as the adverse effects on labor are quite common, PDB should not be given as a routine before delivery, but may be offered liberally when pain in the pudendal area is a main part of the pain of childbirth.