Dose/Response Effects of Intravenous Meperidine on Fetal Heart Rate Variability

Abstract

Active phase of labor indices of fetal heart rate (FHR) variability were studied in demograph-ically similar groups of patients receiving intravenous meperidine in varying doses of 25, 50, 75, and 100 mg. A dose/response relationship has been established for a decrease in indices of fetal heart rate (FHR) variability that is dose related to the onset of change, duration of change, point of maximal change, and return to baseline levels. There is an apparent inverse relationship between level of change and the larger doses of meperidine. Baseline (intercontractional) and total (baseline and intracontractional) data were compared for discrimination of FHR change. Baseline FHR data provided the better overall general resolution of change, whereas total FHR data generally provided an improved resolution between pre- and post-injection values.

Key Words:

• Fetal heart rate
• Meperidine
• Baseline data