The effects on the fetus of an abnormal contraction pattern in the induction of labor with oxytocin

In a group of 29 pregnant women labor was induced with the help of an oxytocin infusion. The intrauterine pressure and fetal heart rate were monitored continuously; at the same time the pH, pCO₂, buffer base, and base excess of the fetus were repeatedly measured. The same measurements were carried out in a control group consisting of 47 pregnant women, who gave birth spontaneously at term without pathology occurring. Thirteen times (nine times in the oxytocin group and four times in the control group) there was initially a period of irregular uterine activity, accompanied by an increased basal tone (≥ 20 mm. Hg). It seems that during this period there may be a deterioration in the acid-base balance of the child. The possible etiology and consequences of these phenomena are discussed with respect to induction by an oxytocin infusion in a pregnancy in which the fetomaternal exchange is already disturbed.