Sublingual nitroglycerine as a tocolytic in external cephalic version: a comparative study

[Breech Presentation: CNGOF Guidelines for Clinical Practice - External Cephalic Version and other Interventions to turn Breech Babies to Cephalic Presentation]

OBJECTIVES

To provide guidelines regarding efficiency and safety of external cephalic version (ECV) attempt and alternatives methods to turn breech babies to cephalic presentation.

METHODS

MedLine and Cochrane Library databases search in French and English and review of the main foreign guidelines between 1980 and 2019.

RESULTS

ECV is associated with a decreasing rate of breech presentation at birth (LE2), and potentially with a lower rate of cesarean section (LE3) without an increase of severe maternal (LE3) and perinatal morbidity (LE3). It is therefore recommended to inform women with a breech presentation at term that ECV should be attempt (Professional consensus). ECV attempt should be performed with immediate access to an operating room for emergency cesarean (Professional consensus). The ECV attempt before 37 weeks, compared to ECV attempt after 37 weeks, increases the rate of cephalic presentation at birth (LE2) but with a small increase risk of moderate prematurity (LE2). ECV attempt should be performed from 36SA (Professional consensus). The main factors associated with successful ECV attempt are multiparity (LE3) and no maternal obesity (LE3). Parenteral tocolysis (β mimetic or atosiban), for ECV attempt at term is associated with a higher success rate (LE2), higher rate of achieved cephalic presentation in labor (LE2) and a lower cesarean section rate (LE2). It is recommended to use parenteral tocolysis for ECV attempt at term in order to increase its success rate (grade B). The ECV attempt is associated with an increase in transient FHR abnormalities (LE3), it is therefore recommended that cardiotocography should be performed prior and during 30minutes after the procedure (Professional consensus). There is no argument for recommending the practice of delayed cardiotocography after ECV attempt (Professional consensus). The risk of significant positivity (>30mL) of the Kleihauer test after ECV attempt is low (<0.1%) (LE3), it is not recommended to systematically perform a Kleihauer test after ECV attempt (professional consensus). In case of RH-1 negative women, it is recommended to ensure systematic RH-1 prophylaxis (Professional consensus). In case of breech presentation at term, acupuncture, moxibustion and postural methods are not effective in reducing breech presentation at birth (LE2), and are therefore not recommended (Grade B).

CONCLUSION

According to the clear benefits and the low risks of ECV attempt, all women with a breech presentation at term should be informed that ECV should be attempted to decrease breech presentation at birth and cesarean section.

Impact of parity on obstetric and neonatal outcome of external cephalic version

This study sought to investigate the impact of parity on the outcome of external cephalic version (ECV) over a 3-year period. In the study, 163 women with singleton uncomplicated breech pregnancy at term were offered ECV and 103 (63%) underwent the procedure. In 42 women, ECV was successful and 74% had a vaginal vertex delivery; whereas 61 women had a failed ECV and none had a vaginal vertex delivery. The probability of vaginal vertex delivery after ECV increased five-fold in nulliparous women (OR 5.2, 95% CI 1 - 42.8) and four-fold (OR 3.8, 95% CI 1.3 - 11.5) in multiparous women. After successful ECV, 50% of nulliparous women and 88.5% of multiparous women had a vaginal vertex delivery (p = 0.006). Neonatal outcome was favourable in all patients. We conclude that parity has little impact on efficacy of ECV, but significantly influences the overall chance of vaginal vertex delivery in women with an uncomplicated breech presentation at term.

Interventions to help external cephalic version for breech presentation at term

BACKGROUND

Breech presentation places a fetus at increased risk. The outcome for the baby is improved by planned caesarean section compared with planned vaginal delivery. External cephalic version attempts to reduce the chances of breech presentation at birth, but is not always successful. Tocolytic drugs to relax the uterus as well as other methods have been used in an attempt to facilitate external cephalic version at term.

OBJECTIVES

To assess the effects of routine tocolysis, fetal acoustic stimulation, epidural or spinal analgesia and transabdominal amnioinfusion for external cephalic version at term on successful version and measures of pregnancy outcome.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register (September 2003) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2003) were searched.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing routine versus selective or no tocolysis; fetal acoustic stimulation in midline fetal spine positions versus dummy or no stimulation; epidural or spinal analgesia versus no regional analgesia; or transabdominal amnioinfusion versus no amnioinfusion for external cephalic version at term.

DATA COLLECTION AND ANALYSIS

The reviewer assessed eligibility and trial quality.

MAIN RESULTS

In six trials, routine tocolysis with beta-stimulants was associated with fewer failures of external cephalic version (relative risk (RR) 0.74, 95% confidence interval (CI) 0.64 to 0.87). The reduction in non-cephalic presentations at birth was not statistically significant. Caesarean sections were reduced (RR 0.85, 95% CI 0.72 to 0.99). In four small trials, sublingual nitroglycerine used as a tocolytic was associated with significant side-effects, and was not found to be effective. Fetal acoustic stimulation in midline fetal spine positions was associated with fewer failures of external cephalic version at term (RR 0.17, 95% CI 0.05 to 0.60). With epidural or spinal analgesia, external cephalic version failure, non-cephalic births and caesarean sections were reduced in two trials but not the other. The overall differences were not statistically significant. No randomised trials of transabdominal amnioinfusion for external cephalic version at term were located.

REVIEWER'S CONCLUSIONS

Routine tocolysis appears to reduce the failure rate of external cephalic version at term. There is not enough evidence to evaluate the use of fetal acoustic stimulation in midline fetal spine positions, nor of epidural or spinal analgesia. Large volume intravenous preloading may have contributed to the effectiveness demonstrated in two of the latter trials.

Sublingual nitroglycerin versus placebo as a tocolytic for external cephalic version: a randomized controlled trial in parous women

OBJECTIVE

The purpose of this study was to evaluate the efficacy of sublingual nitroglycerin as a tocolytic agent for external cephalic version in parous women.

STUDY DESIGN

A double-blinded randomized controlled trial was performed. Patients with parity of >or=1 at 36 to 40 weeks of gestation who were eligible for external cephalic version were included. Patients were randomized to receive either two sublingual sprays of 400 mug of nitroglycerin or two sprays of placebo 3 minutes before the trial of external cephalic version. Rates of successful external cephalic version and side effects were compared between groups.

RESULTS

Of 99 patients in the study, 50 patients received sublingual nitroglycerin, and 49 patients received placebo. There were no differences in maternal age, gestational age, estimated fetal weight, amniotic fluid index, and placental location between the two groups. The success rate of external cephalic version was 48% in the nitroglycerin group compared with 63% in the placebo group (P=.13). There was a higher incidence of headaches in the nitroglycerin group (42% vs 4%, P<.001).

CONCLUSION

Sublingual nitroglycerin was associated with a higher rate of headache and did not improve the rate of successful external cephalic version.

Sublingual nitroglycerin versus intravenous ritodrine as tocolytic for external cephalic version: a double-blinded randomized trial

OBJECTIVE

The purpose of this study was to compare the efficacy of sublingual nitroglycerin with that of intravenous ritodrine as a tocolytic agent for external cephalic version in nulliparous women.

STUDY DESIGN

We performed a double-blinded, randomized trial. Nulliparous patients, between 36 and 40 weeks of gestation, were assigned randomly to receive either (1) an intravenous infusion of ritodrine (111 microg/min) for 20 minutes, followed by two puffs of sublingual placebo or (2) an intravenous infusion of sodium chloride 0.9% (placebo) for 20 minutes, followed by two puffs of sublingual 0.4 mg of nitroglycerin. Three minutes after the administration of the sublingual spray, an external cephalic version was attempted. The rate of successful external cephalic version and side effects was compared between groups.

RESULTS

Of 74 randomly assigned patients, 38 patients received intravenous ritodrine, and 36 patients received sublingual nitroglycerin. Although not statistically significant, the rate of the successful external cephalic version was higher in the ritodrine group compared with the nitroglycerin group (45% vs 25%, P =.075). The rate of headaches was higher in patients who received nitroglycerin (28% vs 8%, P =.02). Mean blood pressure and maternal heart rate were lower in the nitroglycerin group 10 minutes after the administration of the medication. However, there was no significant difference in the rate of palpitations, hypotension, or fetal bradycardia between the two groups.

CONCLUSION

When compared with intravenous ritodrine, sublingual nitroglycerin was associated with a higher rate of headache, lower blood pressure, and a trend toward a lower rate of successful external cephalic version.