Die Vierkanaltokographie in der ungestörten Schwangerschaft

The simultaneous recording of external uterine pressure at four sites of the abdominal wall - known as four-channel tocography - offers new parameters to describe the dynamics of uterine activity. Measurements during delivery and preterm labour have shown that cervical change in labour is correlated to certain patterns of the four-channel parameters (e. g. more frequent and more intensive activity of the upper right uterine segment). Now the question of this study was whether uncoordinated physiological uterine activity in uncomplicated pregnancies could also be characterised by four-channel tocography. 41 healthy women (20 primiparas, 21 multiparas) with normal pregnancy outcome were examined. The two-hour-measurements started at 23 weeks of gestation and were repeated every four weeks until term. The electronically stored tocometric signals were automatically processed by special computer software for recognition and quantification of the contraction patterns. Multiparas had 6.7, primiparas had 10.5 contractions per hour (p < 0,001). These frequencies showed no clear correlation to the gestational age. The rate of global contractions developing simultaneously in at least three uterine segments was rather low (≤28%), but generally higher in the primiparae. Both groups had an increase in activity of the upper right area of the uterus shortly before delivery as seen in increased participation, more frequent onset and higher intensity of contractions. Obviously, uterine contractions set in early during pregnancy with weak and local but frequent contractions which do not become significantly more frequent in the course of pregnancy. For this reason, the commonly practised method of judging the risk of preterm birth just by counting contractions in a routine CTG should be critically reconsidered. Furthermore, uterine activities seem to develop in different ways in primi- and multiparas which until now has not been described in literature. Certainly, four-channel tocography can contribute to further research on these phenomena in order to differentiate more precisely between pathological and physiological contractions, thus avoiding tocolysis or at least tocolysis with unnecessary high dosages.