[Differential peridural analgesia for vaginal delivery. A randomised study of its influence on the progress and mode of delivery (author's transl)].

This randomised study of 611 deliveries deals with the side effects of a modified extradural analgesic technique. The modification is based on a flexible reduction of local anaesthetic concentration (bupivacaine) which allows a reliable analgesia without a marked loss of labour sensation and bearing down reflex. Randomisation was achieved by offering this analgesia to the parturients in an alternating 24 hours rhythm. Statistical comparisons were carried out for the following groups of deliveries: 1. for deliveries on both of the two alternating days (Group A). 2. for deliveries with and without extradural analgesia of the peridural days (Group B). - 3. for all deliveries with and without extradural analgesia (Group C). - 4. For deliveries without extradural analgesia on "peridural days" and on "alternating days" (Group D). - The main subjects of investigation were the duration of the two stages of delivery, the dynamics of both the cervical dilation and the movement of the fetal head and the frequency, modes and causes of operative and instrumental deliveries. The safety of the analgesic technique was investigated by evaluating its influence on the status of the newborn and on the maternal regulation of body temperature and circulation. The results were obtained as follows: 1. In the group of parturients who had chosen extradural analgesia several antenatal factors accumulated which evidently had a greater influence on the course of delivery than the analgesic technique itself. - 2. The low concentration of local anaesthetic adapted to the labour pain produced a sufficient analgesia in almost every case. - 3. The duration of both stages of delivery was not altered directly by this technique. An average increase of the duration of the second stage by 116 minutes was due to postponed indications of instrumental and operative deliveries by analgesia. - 4. There was no influence on the overall frequency of operative and instrumental deliveries. Extradural analgesia, however, significantly reduced the frequency of caesarean sections to the same extent as it increased instrumental deliveries from the bottom of the pelvis. - 5. The extradural analgesia had no influence on the status of the newborn. - 6. The regulatory mechanisms of circulation and body temperature were not altered by this dosage of extradural analgesia.