[Management of second stage of labour: observations, reflections, advices (author's transl)].

All vaginal deliveries of the Department of Obstetrics and Gynecology of the University Basel (N = 4081) during the year 74/73 and of the University Tübingen (N = 3249) 75/74 were analysed using an IBM-system 370/135 Only alive singletons beyond the 28th week of gestation were analysed. Clinical management was quite different in the two departments; the incidence of vaginal operations (Basal 11.2%, Tübingen 12.6%), however, as well as the distribution of pH-values and Apgar-scores after 1 min were quite similar. Basel: Acidotic risk (i.e. pHUA less than 7.200) 13.5%, severe acidotic risk (i.e. pHUA less than 7.100) 1.55%, low Apgar-scores (1--3) 0.7%. Tübingen: :12.3%, 2.11%, 1.6%. 3.5% of all parturients (Basel) had duration of second stage of labour with active maternal pressure support lasting more than 30 min. In two highly selected samples differing only with regard to the occurrence of cord-entanglements at birth (N1 = 1755, N2 = 1098) the association (rank correlation method according to Kendall) between the parameters of the fetal acid-base balance and the duration of second stage of labour as well as duration of the period with "active bearing down" was studied. Without cord encirclements pH in the umbilical artery fall --0.087 and in the umbilical vein --0.115 units and with cord complications the values amounted to --0.062 (UA) and --0.120 (UV) respectively pro 60 min duration of second stage with "bearing down efforts". Analogous computations for pCO2, pO2 and HbO2 are presented. Apgar-scores in these samples showed a very loose connection with the time variables. From these data the conclusion is drawn that the indication to perform vaginal operations for termination of delivery should not primarily be governed by the factor time but rather by the whole obstetrical situation i.e. the possible fetal risk of the intervention. This holds only if maternal welfare is established and fetal well being is monitored continuously.