Terbutaline Increases Success of External Cephalic Version
Synopsis: Subcutaneous terbutaline given before an attempted external cephalic version significantly increases the success of the procedure.
Source: Fernandez CO, et al. Obstet Gynecol 1997;90: 775-779.
To determine whether subcutaneous terbutaline (0.25 mg) would increase the success rate of external cephalic version (ECV) for a breech presentation at term, Fernandez and associates conducted a prospective, randomized, and blind placebo-controlled trial. Of 103 women in the study, 52 received terbutaline and 51 received placebo.ECV was successful in 27 of the 52 (52%) women receiving terbutaline, a rate significantly higher than that of the placebo group, 14 of 51 (27%). The rate of cesarean delivery was also significantly lower in the group receiving terbutaline as compared to the placebo, 30 of 52 (58%) vs. 39 of 51 (76%). Of 89 patients who had both preversion and postversion Kleihauer-Betke stains, 16% or 18% had an increase after the procedure, indicating that fetal-maternal hemorrhage had occurred. The likelihood of fetal-maternal hemorrhage was not different in the treatment groups.
Fernandez et al conclude that subcutaneous terbutaline given before an attempted ECV significantly increases the success of the procedure.
COMMENT BY STEVEN G. GABBE, MD
In many institutions, nearly all patients with a breech presentation are delivered by cesarean section. Of all cesarean deliveries performed in this country, approximately 10-15% are done for breech presentation. ECV performed at 37-38 weeks gestation can significantly reduce the number of cesarean deliveries performed for this indication. The procedure is usually attempted after 37 weeks. An ultrasound is done to estimate fetal weight, localize the placenta, and determine amniotic fluid volume. Fetal heart rate is then monitored for 30 minutes to assure it is normal.The procedure is usually performed in the morning with the patient NPO and anesthesia aware, should an emergency cesarean delivery be necessary. The obstetrician, often with the aid of an assistant, then attempts to elevate the breech and turn the fetus using a forward roll or backflip technique. Ultrasound is used during the procedure to evaluate fetal position and monitor the fetal heart rate. The ECV is halted should fetal heart rate decelerations be detected. The fetal heart rate is followed for approximately one hour after the procedure, and Rhogam is administered to Rh-negative unsensitized women.
ECV is successful in approximately 70% of attempts. The likelihood of
failure is greater in patients who have decreased amniotic fluid, are obese,
or when the breech is engaged in the pelvis. Fernandez et al now report
that terbutaline administered prior to the version increases the success
rate, although the overall success rate in their study was lower than that
reported in the literature. They attribute this difference to the procedure
being performed by less experienced house officers. Of note, the reported
rate of fetal-maternal hemorrhage was also higher in this study. It is
usually reported to be approximately 5%.
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