American journal of obstetrics and gynecology
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Am. J. Obstet. Gynecol. · Dec 1990
Randomized Controlled Trial Comparative Study Clinical TrialInduction of labor with pulsatile oxytocin.
In a prospective, randomized study, 106 patients underwent induction of labor with either pulsed (every 8 minutes) (n = 50) or continuous (n = 56) intravenous infusion of oxytocin. Maternal characteristics, gestational age at induction, induction-delivery interval, analgesia for labor, cesarean section rates, and newborn characteristics were similar in both groups. The mean +/- SEM total oxytocin administered was significantly less in the pulsed group (3564 +/- 487 mU) than in the continuous group (7684 +/- 844 mU; p less than 0.0001); the average dose of oxytocin administered per minute was significantly lower in the pulsed group (3.9 +/- 0.3 mU/min) than in the continuous group (7.8 +/- 0.4 mU/min; p less than 0.0001); the peak or highest administered dose of oxytocin expressed per minute was also signficantly lower in the pulsed group (9.6 +/- 0.8 mU/min) than in the continuous group (14.1 +/- 0.7 mU/min; p less than 0.0001). ⋯ Uterine hyperstimulation occurred infrequently in both groups (3.6% to 4.0%). The pulsed group required a significantly smaller infusion volume (25 +/- 14 ml) than the continuous group (780 +/- 84 ml; p less than 0.0001). Thus pulsatile administration uses significantly less oxytocin and infusion fluid but is as effective and safe as continuous infusion.
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Am. J. Obstet. Gynecol. · Dec 1990
Inhibition of spontaneous uterine contractions during the last trimester in pregnant baboons by an oxytocin antagonist.
The effect of a potent oxytocin antagonist, produced in our laboratories, on spontaneous uterine contractions in the pregnant baboon was examined. Three types of uterine contractions were studied: immediately after operation, during the nocturnal period, and near or at labor. ⋯ In contrast, uterine contractions immediately after operation were diminished by only 60% within 60 minutes after the oxytocin antagonist. These results indicate that the oxytocin antagonist is a potent inhibitor and suggest that oxytocin is a primary regulator of spontaneous nocturnal and labor uterine contractions in the pregnant baboon.