Can the Oxytocin Challenge Test Serve as the Primary Method for Managing High-Risk Pregnancies?

The purpose of this investigation was to determine whether the oxytocin challenge test (OCT) could serve as the primary method for managing pregnancies characterized by possible placental insufficiency. One hundred and five patients underwent 225 oxytocin challenge tests; no perinatal deaths occurred. Eight tests were positive, 21 suspicious, and 196 negative. Because of data obtained in a preliminary study, all 8 fetuses with positive tests were delivered by cesarean section. Four of the 8 had repetitive suspicious tests prior to a positive test, suggesting that uteroplacental function may deteriorate gradually. Urinary excretion of estriol did not decrease significantly in any patient, suggesting that the OCT is a more sensitive indicator of placental function than excretion of estriol. Except for patients with preeclampsia who were induced for maternal indications, all pregnancies with a negative OCT were allowed to terminate spontaneously. Five of the 97 fetuses with negative tests developed late-onset deceleration patterns during labor. This indicates that a negative OCT will not necessarily predict fetal tolerance to labor, contrary to assertions made by some other investigators. It is concluded that the OCT can serve as the primary method for assessing the fetal status in pregnancies characterized by placental insufficiency.