Clinical features of the reactive positive contraction stress test

During a five-year period, 2815 patients undergoing 5685 fetal heart rate (FHR) tests produced 147 positive contraction stress tests. Baseline FHR patterns were considered reactive if three or more accelerations occurred during 30 minutes of the contraction stress test and nonreactive if fewer or no accelerations were noted. There were 75 reactive positive contraction stress tests and 72 nonreactive positive contraction stress tests. Both groups were promptly delivered, generally (91%) within 24 hours of the last test. Fetuses producing reactive positive patterns tended to be more mature, larger, and most frequently tested for postmaturity. Fetuses with nonreactive positive patterns had significantly higher rates of perinatal mortality and morbidity, growth retardation, and cesarean deliveries; they were frequently carried by hypertensive mothers. Each group was analyzed according to deceleration: Contraction ratio, and deceleration: Contraction ratio deciles from 30 to 100% were examined. Perinatal complications increased progressively with higher deceleration: Contraction ratios, irrespective of baseline reactivity; however, nonreactive fetuses in any deceleration: Contraction ratio decile had more frequent perinatal compromise than their reactive counterparts. The lack of specificity (26 poor outcomes in 75 cases) associated with the reactive positive contraction stress tests encourages more frequent attempts at vaginal delivery; in this group, 64 of 71 patients had successful vaginal deliveries. Furthermore, the high incidence of good fetal outcome in the reactive positive group suggests that the urgency of delivery in such circumstances be reassessed and that other fetal-maternal indicators be considered in delivery decisions.