Fetal bradycardia and uterine hyperactivity following subarachnoid administration of fentanyl during labor - Case report

Background and Objectives. Changes in uterine tone have been postulated as the cause of fetal bradycardia following subarachnoid administration of fentanyl for labor analgesia. Such a case occurred in a 20-year-old parturient with an intrauterine pressure catheter in place. Methods. The patient was given intravenous terbutaline, after which contractions ceased for 20-30 minutes and then resumed. Results. The patient underwent successful cesarean delivery. Retrospective analysis of the data revealed a significant increase in uterine tone and contractions following fentanyl administration. Conclusions. This case supports the view that changes in uterine tone, producing a hyperdynamic contractile state and a resulting decrease in uteroplacental perfusion, may explain the fetal bradycardia following subarachnoid opioid administration. Cases that do not resolve spontaneously may respond to intravenous terbutaline.