II. Multifactorial analysis of intrapartum fetal heart rate tracings.

The first 30 minutes and the last 30 minutes of 1,996 intrapartum FHR tracings were analyzed for baseline FHR, variability (amplitude and frequency of oscillations), accelerations, and decelerations. A modified FHR scoring system incorporating these FHR features was employed. According to the association between various FHR scores and the incidence of low Apgar scores, FHR patterns were grouped into three basic categories with distinct prognostic significance: (1) normal FHR patterns, (2) compensated distress patterns, and (3) decompensated distress patterns. It is concluded that the prognostic significance of FHR tracings is increased by incorporating several FHR monitoring criteria in the analysis.