[Role of rheobase measurement in recording and controlling premature labour (author's transl)].

A rise in the rate of premature childbirth from six to eight per cent was recordable in some region of the GDR, in recent years. This figure added to the statistical record of perinatal mortality and accounts for something between 60 and 80 per cent. -- Aggravating neurovegetative irritability, next to foetal and maternal causes as well as to factors of the environment, has been quoted as the major cause of premature onset of labour. Rise in vegetative tension may be determined by means of rheobase measurement of neuromuscular excitability, on the basis of central nervous coupling of the striated muscle. -- Rheobase measurements were applied to pregnant women and statistically evaluated, between 1977 and 1979. -- The RS 12-1 electrostimulator and AP 202 arterial pulse indicator were used for rheobase measurement proper. Contractions were recorded by means of the DT-500 tocograph and Hewlett-Packard cardiotocograph. -- As a whole, 167 rheobase data were recorded from 101 patients. The rheobase data recorded from patients with premature onset of labour were significantly below those obtained from women with normal course of pregnancy. The rheobase threshold (critical value) may be defined as 3.5 mA. Statistical evaluation of follow-up rheobase measurements on pregnant women with premature labour showed that the values underwent significant change towards the normal in response to tocolytic therapy. Decline in rheobase in response to tocolytic therapy will be followed, with high probability, by termination of pregnancy. -- Rheobase is a parameter which was found to correlate properly with the risk of premature childbirth and, therefore, should be used in diagnosis (score to determine risk of premature childbirth) and therapy (supervision of tocolytic treatment).