Sinusoidal fetal heart rate pattern associated with butorphanol administration.

One hundred nineteen fetal heart rate monitor tracings from term-pregnant patients in labor were reviewed by two independent observers to test the hypothesis that Stadol administration to mothers does not result in sinusoidal fetal heart rate pattern. There was agreement with regard to the interpretation of the tracings in 106 instances. Fifty-one patients received intravenous Stadol for narcotic analgesia. Seventy-five percent of these patients demonstrated a transient sinusoidal fetal heart rate pattern after Stadol administration. In a small number of patients, this pattern recurred either with or without additional Stadol treatment. In contrast, patients who did not receive Stadol therapy (N = 55) demonstrated a significantly lower incidence of sinusoidal fetal heart rate pattern (13%), the duration of which was significantly shorter than that seen in the former group. From these we conclude that Stadol therapy during labor is strongly associated with the appearance of sinusoidal fetal heart rate pattern. There were no short-term maternal or neonatal adverse sequelae. In the absence of other fetal heart rate signs suggestive of fetal distress, the presence of sinusoidal fetal heart rate pattern after Stadol administration does not indicate fetal hypoxia.