A Prospective Randomized Study to Examine the Success Rate of External Cephalic Version for Breech Presentation at Term Presentation: Spinal Analgesia Versus No Analgesia
A Prospective Randomized Study to Examine the Success Rate of External Cephalic Version for Breech Presentation at Term Presentation: Spinal Analgesia Versus No Analgesia
The purpose of this study is to examine whether spinal anesthesia affects the chances of successful external cephalic version (ECV) of a breech presenting fetus.
Two study groups will be included; one will receive spinal anesthesia, the other will not. The non-spinal group will be permitted to cross over if ECV procedure is painful.
The main outcome is success of ECV.
The rate of breech presentations in the general population of parturients has remained unchanged at 3%. However, the recent finding that the fetus has an increased morbidity during a vaginal delivery when compared with Cesarean section [1] has driven obstetricians towards the decision that all breech presentations will be delivered surgically. The morbidity of the mother with a breech presentation is not increased with a vaginal delivery; in fact the maternal morbidity associated with surgery is higher than after a vaginal delivery [2,3]. Subsequent pregnancies are automatically deemed high risk due to the presence of a uterine scar [4].
In an attempt to reduce the need for surgery with a breech presentation, the only option available in the current climate, where a vaginal delivery is out of the question, is to attempt to convert the fetal presentation from a breech to a vertex (head) presentation.
This technique may result in the premature onset of labor, which would require emergent surgery, and there is also a risk of placental abruption [5]. Following external cephalic version (ECV), the fetus may spontaneously return to the breech position. The success rates vary from 30% in nulliparous women, to 67% in multiparous women [6].
In an attempt to improve the success rates of ECV, authors have previously utilized regional anesthesia techniques [7-11]. Regional analgesia relaxes the stomach wall, and provides pain relief during the ECV procedure. The use of regional analgesia has claimed to increase the success rate of ECV to up to 80% [7]. However, other studies found no differences in success rates between the group which received regional analgesia and the group that did not [12]. All of these studies looked at women who have reached at least 36 weeks gestation. Despite the well-recognized differences in success rates between nulliparous and multiparous women, none of the studies that have examined regional analgesia with ECV have controlled for this factor in their studies. Thus the success rates, and any increase in success rates that is seen, may purely be a function of the number of multiparous women enrolled in the study.
This study will compare ECV separately in both a nulliparous and multiparous population, at term, and compare the success rates when spinal anesthesia is employed, versus no anesthesia. Success is defined as the conversion of a breech to vertex presentation.
Methods:
The study is prospective and randomized. Both nulliparous and multiparous women will be enrolled in the study, however each group will be randomized separately either to receive, or not receive, neuraxial (spinal) analgesia. Approximately 50 nulliparous and 50 multiparous women will be enrolled in each of the two groups. Randomization will be decided according to the final number of the patient's identity number (odd numbers will receive spinal analgesia, and even numbers will not receive analgesia). Written informed consent will be obtained prior to inclusion in the study.
All women will receive 20 mg nifedipine orally 30 minutes before the procedure according to hospital protocol. They will have continuous fetal heart rate monitoring.
After randomization, the spinal analgesia group (S) will receive 1000 cc Ringer's Lactate solution. Additional monitoring will include ECG, non-invasive blood pressure and pulse oximetry. In the sitting position, spinal anesthesia will be performed using a pencil-point needle. 7.5 mg plain bupivacaine (Astra) will be injected intrathecally. The patient will be reclined in a left lateral tilt, and the table will be adjusted in order to encourage the spreading of the anesthetic drug to the T6 level. Once anesthesia is attained, the ECV procedure will be performed.
The group assigned to receive no analgesia (N) will receive 1000 cc Ringer's Lactate solution prior to the ECV procedure. These women will be monitored in the same way as group S. ECV will be performed as usual. Women who are at an advanced stage of pregnancy, or have some other obstetric indication for delivery on the day of the ECV, will be offered their spinal analgesia with the addition of an epidural catheter (CSE-combined spinal epidural technique). This technique is part of regular daily anesthesia practise, and allows for the administration of additional analgesia after the effect of the spinal anesthesia has passed. This would be sufficient either for labor or for Cesarean section analgesia.
2 obstetricians, at least one of whom has experience with the procedure, will perform the ECV, with the aid of ultrasound surveillance. The ECV procedure will be halted if any of the following occurs: fetal bradycardia, placental abruption, and failure of ECV.
Women from group N who are unable to tolerate the procedure due to discomfort will be provided with regional analgesia, as described above.
Results:
The results will be analyzed on an intention to treat basis. Demographic data including age, parity, previous breech delivery, fetal size at 32 week ultrasound scan, and estimated amount of amniotic fluid will be collected and analyzed by ANOVA.
Data regarding success of ECV and complications will be analyzed using student t test and Chi square. Significance will be considered as p < 0.05.
Conclusion:
Success of the anesthesia-assisted ECV technique will be defined as a significant increase in the success rate of ECV, without a significant increase in the complication rate.
References:
Inclusion Criteria:
Exclusion Criteria: