[Obstetrical anaesthesia. Their place in the conduct of labour (author's transl)].

After having made an historical study of the principal works coming from the School in Toulouse concerning obstetrical anaesthesia, one can make an account of the criteria for fetal risk. These have been established by comparing with a standard that determines the physical and biological parameters found in normal labour. The fetal risk has been studied for four types of anaesthesia progressively. These are : general anaesthesia with Pentothal, general anaesthesia with Gamma OH, neuroleptanalgesia and finally epidural anaesthesia. By comparison with a normal standard, the evolution of the parameters concerning uterine contraction, the changes in the fetal heart rate the, acid-base balance of the fetal blood and how it changes, and the Apgar score have been studied for each type of anaesthesia. The same has been done for maternal risk. After having completed this study we have come to the conclusion that there is no single anaesthetic that should particularly be recommended, and that for every phase of labour : before labour starts and after labour has been confirmed, and at the end of the first stage of labour, a different form of anaesthesia may well be indicated. Above all, the skill of the anaesthetist and of the obstetrician influence the efficiency of the anaesthetic.