Clinical experience with the oxytocin challenge test

Abstract

The oxytocin challenge test may provide information regarding fetal well-being which is helpful to the obstetrician. In this study, there were 65 negative tests on 43 patients, and those fetuses with negative tests uniformly did well, if there were no congenital anomalies or complications in the mechanics of delivery. There were 21 positive tests on 15 patients. A positive test was significant in that it confirmed the clinical impression that the fetus was existing in a markedly unfavorable environment, heralded a fall in maternal estriol excretion and, in 3 instances, signified impending intrauterine death. Loss of beat-to-beat variability of the fetal heart rate may increase the ominous prognosis of a positive test. In instances where the 24 hour urinary estriol excretion is chronically low and therefore of questionable value in timing delivery, the test provides a physiologic stress to the fetus, the response to which may reflect the degree of fetoplacental respiratory reserve. Or, when a positive oxytocin challenge test occurs in the face of normal 24 hour estriol production, the likelihood of subsequent fetal deterioration seems high.