The significance of fetal heart rate-uterine contraction (FHR-UC) monitoring as a means of predicting the condition of the fetus during labor was studied by correlating 460 fetal pH determinations obtained from 216 patients with the analysis of the 20-minute FHR-UC record preceding the fetal scalp blood sample. Both qualitative and quantitative analyses of the FHR-UC record were performed. The results indicate a less than 10% chance of fetal pH ≤7.250 with a normal baseline FHR and no periodic changes or with periodic accelerations, early decelerations, and uncomplicated baseline bradycardia or tachycardia. Variable or delayed decelerations with a total surface area (TSA) of 1–100 for the 20-min period were associated with a fetal pH ≤ 7.250 in 23 and 34% of cases, respectively. Variable or delayed decelerations with a TSA 100 had a 35 or 47% chance of fetal pH ≤ 7.250. It is concluded that FHR-UC monitoring can be used to screen the innocuous from the ominous periodic change but that fetal scalp blood pH must be obtained to identify accurately the true from the false-positive ominous pattern.
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