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

Ritodrine in external cephalic version: is it effective and safe?

Objective

The external cephalic version (ECV) has been shown to lower the likelihood of cesarean section requirements among pregnant women with breech presentations. In the current study, we investigated the effectiveness and safety of ritodrine as a tocolytic for ECV.

Methods

A total of 407 pregnant women with breech presentations, who had no contraindications for ECV, were enrolled in this study. Multivariable logistic regression analyses were used to assess the impact of ritodrine use on the safety and efficacy of ECV.

Results

The overall success rate was 67.6%, and ritodrine use was associated with significantly higher odds of successful ECV after adjusting for confounders. Moreover, using ritodrine did not increase the risk of adverse effects, including temporary changes in fetal heart rate, need for elective or emergency cesarean section due to fetal distress during ECV, low Apgar scores, and perinatal mortality.

Conclusion

Our results suggest that using ritodrine as a tocolytic during ECV may increase the likelihood of ECV success and may not increase adverse perinatal outcomes.

Comparison of Nitroglycerin and Terbutaline for External Cephalic Version in Women Who Received Neuraxial Anesthesia: A Retrospective Analysis

External cephalic version is a technique that decreases the need for cesarean delivery in patients with breech presentation. Several techniques exist to increase the success of external cephalic version; however, there are no studies comparing different tocolytics in patients who also received neuraxial anesthesia. We, therefore, performed a review of 198 patients who presented for external cephalic version and compared their success rates based on the tocolytic medication utilized. The external cephalic version success rate for patients who received terbutaline was significantly higher than for those who received nitroglycerin (N [%]: 57 [65.6] terbutaline group versus 40 [36.0] nitroglycerin group; P < .001).

Atosiban versus ritodrine as tocolytics in external cephalic version

Objective: To assess the efficacy of atosiban versus ritodrine as tocolytics in external cephalic version (ECV).Materials and methods: A prospective comparative trial was carried out in a tertiary hospital. 430 women with singleton breech pregnancies ≥36 weeks were recruited for ECV, 215 with ritodrine and 215 with atosiban as tocolytic agents. The efficacy, complications and perinatal outcomes were compared between both groups. The associations between variables were analyzed using the chi-square test (χ²) (qualitative), Student's t test (quantitative, parametric) or Mann-Whitney test (nonparametric). Statistical significance was established as p < .05.Results: The overall ECV success rate was 47.9% (206/430), 46.0% in the atosiban group (99/215) and 49.8% in the ritodrine group (107/215). This difference showed no statistical significance (p = .440). A higher rate of uterine contractions after the maneuver was observed in the atosiban group (34.4 versus 22.8%; p = .008), but without clinical relevance. Perinatal outcomes were similar in both groups, with no significant differences.Conclusion: Atosiban and ritodrine showed similar efficacy as tocolytic agents in ECV, with no differences in complications and perinatal outcomes between these two agents.

Interventions for helping to turn term breech babies to head first presentation when using external cephalic version

BACKGROUND

Breech presentation is associated with increased complications. Turning a breech baby to head first presentation using external cephalic version (ECV) attempts to reduce the chances of breech presentation at birth so as to avoid the adverse effects of breech vaginal birth or caesarean section. Interventions such as tocolytic drugs and other methods have been used in an attempt to facilitate ECV.

OBJECTIVES

To assess, from the best evidence available, the effects of interventions such as tocolysis, acoustic stimulation for midline spine position, regional analgesia (epidural or spinal), transabdominal amnioinfusion, systemic opioids and hypnosis, or the use of abdominal lubricants, on ECV at term for successful version, presentation at birth, method of birth and perinatal and maternal morbidity and mortality.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2014) and the reference lists of identified studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing the above interventions with no intervention or other methods to facilitate ECV at term.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality. Two review authors independently assessed for inclusion all potential studies identified as a result of the search strategy and independently extracted the data using a specially designed data extraction form.

MAIN RESULTS

We included 28 studies, providing data on 2786 women. We used the random-effects model for pooling data because of clinical heterogeneity between studies. A number of trial reports gave insufficient information to allow clear assessment of risk of bias. We used GradePro software to carry out formal assessments of quality of the evidence for beta stimulants versus placebo and regional analgesia with tocolysis versus tocolysis alone.Tocolytic parenteral beta stimulants were effective in increasing cephalic presentations in labour (average risk ratio (RR) 1.68, 95% confidence interval (CI) 1.14 to 2.48, five studies, 459 women, low-quality evidence) and in reducing the number of caesarean sections (average RR 0.77, 95% CI 0.67 to 0.88, six studies, 742 women, moderate-quality evidence). Failure to achieve a cephalic vaginal birth was less likely for women receiving a parenteral beta stimulant (average RR 0.75, 95% CI 0.60 to 0.92, four studies, 399 women, moderate-quality evidence). No clear differences in fetal bradycardias were identified, although this was reported for only one study, which was underpowered for assessing this outcome. Failed external cephalic version was reported in nine studies (900 women), and women receiving parenteral beta stimulants were less likely to have failure compared with controls (average RR 0.70, 95% CI 0.60 to 0.82, moderate-quality evidence). Perinatal mortality and serious morbidity were not reported. Sensitivity analysis by study quality was consistent with overall findings.For other classes of tocolytic drugs (calcium channel blockers and nitric oxide donors), evidence was insufficient to permit conclusions; outcomes were reported for only one or two studies, which were underpowered to demonstrate differences between treatment and control groups. Little evidence was found regarding adverse effects, although nitric oxide donors were associated with increased risk of headache. Data comparing different tocolytic drugs were insufficient.Regional analgesia in combination with a tocolytic was more effective than the tocolytic alone for increasing successful versions (assessed by the rate of failed ECVs; average RR 0.61, 95% CI 0.43 to 0.86, five studies, 409 women, moderate-quality evidence), and no difference was identified in cephalic presentation in labour (average RR 1.63, 95% CI 0.75 to 3.53, three studies, 279 women, very low-quality evidence), caesarean sections (average RR 0.74, 95% CI 0.40 to 1.37, three studies, 279 women, very low-quality evidence) nor fetal bradycardia (average RR 1.48, 95% CI 0.62 to 3.57, two studies, 210 women, low-quality evidence), although studies were underpowered for assessing these outcomes. Studies did not report on failure to achieve a cephalic vaginal birth (breech vaginal deliveries plus caesarean sections) nor on perinatal mortality or serious infant morbidity.Data were insufficient on the use of regional analgesia without tocolysis, vibroacoustic stimulation, amnioinfusion, systemic opioids and hypnosis, and on the use of talcum powder or gel to assist external cephalic version, to permit conclusions about their effectiveness and safety.

AUTHORS' CONCLUSIONS

Parenteral beta stimulants were effective in facilitating successful ECV, increasing cephalic presentation in labour and reducing the caesarean section rate, but data on adverse effects were insufficient. Data on calcium channel blockers and nitric acid donors were insufficient to provide good evidence.The scope for further research is clear. Possible benefits of tocolysis in reducing the force required for successful version and possible risks of side effects need to be addressed further. Further trials are needed to compare the effectiveness of routine versus selective use of tocolysis and the role of regional analgesia, fetal acoustic stimulation, amnioinfusion and abdominal lubricants, and the effects of hypnosis, in facilitating ECV. Although randomised trials of nitric oxide donors are small, the results are sufficiently negative to discourage further trials. Intervention fidelity for ECV can be enhanced by standardisation of the techniques and processes used for clinical manipulation of the fetus in the abdominal cavity and ought to be the subject of further research.

Interventions for helping to turn term breech babies to head first presentation when using external cephalic version

BACKGROUND

Breech presentation is associated with increased complications. Turning a breech baby to head first presentation using external cephalic version (ECV) attempts to reduce the chances of breech presentation at birth, and reduce the adverse effects of breech vaginal birth or caesarean section. Tocolytic drugs and other methods have been used in an attempt to facilitate ECV.

OBJECTIVES

To assess interventions such as tocolysis, fetal acoustic stimulation, regional analgesia, transabdominal amnioinfusion or systemic opioids on ECV for a breech baby at term.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2011) and the reference lists of identified studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing the above interventions with no intervention or other methods to facilitate ECV at term.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality. Two review authors independently assessed for inclusion all potential studies identified as a result of the search strategy and independently extracted the data using a designed data extraction form.

MAIN RESULTS

We included 25 studies, providing data on 2548 women. We used the random-effects model for pooling data due to clinical heterogeneity in the included studies in the various comparisons. The overall quality of the evidence was reasonable, but a number of assessments had insufficient data to provide an answer with any degree of assurance.Tocolytic drugs, in particular betastimulants, were effective in increasing cephalic presentations in labour (average risk ratio (RR) 1.38, 95% confidence interval (CI) 1.03 to 1.85, eight studies, 993 women) and in reducing the number of caesarean sections (average RR 0.82, 95% CI 0.71 to 0.94, eight studies, 1177 women). No differences were identified in fetal bradycardias (average RR 0.95, 95% CI 0.48 to 1.89, three studies, 467 women) although the review is underpowered for assessing this outcome. We identified no difference in success, cephalic presentation in labour and caesarean sections between nulliparous and multiparous women. There were insufficient data comparing different groups of tocolytic drugs. Sensitivity analyses by study quality agreed with the overall findings.Regional analgesia in combination with a tocolytic was more effective than the tocolytic alone in terms of increasing successful versions (assessed by the rate of failed ECVs, average RR 0.67, 95% CI 0.51 to 0.89, six studies, 550 women) but there was no difference identified in cephalic presentation in labour (average RR 1.63, 95% CI 0.75 to 3.53, three studies, 279 women) nor in caesarean sections (average RR 0.74, 95% CI 0.40 to 1.37, three studies, 279 women) or fetal bradycardia (average RR 1.48, 95% CI 0.62 to 3.57, two studies, 210 women).There were insufficient data on the use of vibroacoustic stimulation, amnioinfusion or systemic opioids.

AUTHORS' CONCLUSIONS

Betastimulants, to facilitate ECV, increased cephalic presentation in labour and birth, and reduced the caesarean section rate in both nulliparous and multiparous women, but there were insufficient data on adverse effects. Calcium channel blockers and nitric acid donors had insufficient data to provide good evidence. At present we recommend betamimetics for facilitating ECV.There is scope for further research. The possible benefits of tocolysis to reduce the force required for successful version and the possible risks of maternal cardiovascular side effects, need to be addressed further. Further trials are needed to compare the effectiveness of routine versus selective use of tocolysis, the role of regional analgesia, fetal acoustic stimulation, amnioinfusion and the effect of intravenous or oral hydration prior to ECV.Although randomised trials of nitroglycerine are small, the results are sufficiently negative to discourage further trials.

Clinical use of nitric oxide donors and L-arginine in obstetrics

Nitric oxide (NO) is a free radical that plays a fundamental role in human physiology, being involved in the homeostasis of different functions. In obstetrics this molecule is determinant in the physiology of labor and cervical ripening; it possibly plays a fundamental role in the etiology of preeclampsia and intrauterine growth restriction, and it could also be utilized in view of its ability to induce smooth muscle relaxation. Several clinical trials have ascertained the ability of the topical application of NO donors to promote cervical ripening, and also labor induction. There is much less evidence on the use of NO donors in the vascular complications of pregnancy, either as prophylactics or therapeutic agents. Due to the capacity of NO to promote relaxation of smooth muscle, NO donors have been employed as tocolytics with performance similar to other agents. Moreover, although anecdotal, the experience of sudden uterine relaxation using NO donors in obstetric emergencies remains of great clinical value.

Randomized comparison of intravenous terbutaline vs nitroglycerin for acute intrapartum fetal resuscitation

OBJECTIVE

The purpose of this study was to compare terbutaline and nitroglycerin for acute intrapartum fetal resuscitation.

STUDY DESIGN

Women between 32-, 42 weeks' gestation were assigned randomly to 250 microg of terbutaline or 400 microg nitroglycerin intravenously for nonreassuring fetal heart rate tracings in labor. The rate of successful acute intrapartum fetal resuscitation and the maternal hemodynamic changes were compared. Assuming a 50% failure rate in the terbutaline arm, we calculated that a total of 110 patients would be required to detect a 50% reduction in failure in the nitroglycerin group (50% to 25%), with an alpha value of .05, a beta value of .20, and a power of 80%.

RESULTS

One hundred ten women had nonreassuring fetal heart rate tracings in labor; 57 women received terbutaline, and 53 women received nitroglycerin. Successful acute resuscitation rates were similar (terbutaline 71.9% and nitroglycerin 64.2%; P = .38). Terbutaline resulted in lower median contraction frequency per 10 minutes (2.9 [25-75 percentile, 1.7- 3.3] vs 4 [25-75 percentile, 2.5- 5]; P < .002) and reduced tachysystole (1.8% vs 18.9%; P = .003). Maternal mean arterial pressures decreased with nitroglycerin (81-76 mm Hg; P = .02), but not terbutaline (82-81 mm Hg; P = .73).

CONCLUSION

Although terbutaline provided more effective tocolysis with less impact on maternal blood pressure, no difference was noted between nitroglycerin and terbutaline in successful acute intrapartum fetal resuscitation.

Drug therapy during labor and delivery, part 2

PURPOSE

The drug therapy of common conditions and complications during labor and delivery and the fetal and neonatal effects of this therapy are examined.

SUMMARY

The pharmacologic therapy of common conditions that occur in labor and delivery primarily involves oxytocin and prostaglandins for cervical ripening and labor induction and systemic and regional narcotic analgesics for pain. Because most medications used in women during labor and delivery do not have Food and Drug Administration-approved labeling, pharmacists should understand the benefits and limitations of medications used in the mother. Although induction and augmentation of labor and the control of pain often require drug therapy, other, less frequent, complications may occur in labor. Drug therapies for these complications include anti-infective agents to treat maternal infection and prevent neonatal diseases; antiretrovirals to reduce perinatal HIV-1 transmission from the mother to the fetus; corticosteroids to prevent fetal lung immaturity; antihypertensives to treat preeclampsia; anticonvulsants to treat eclampsia; antibiotics to prolong pregnancy and improve neonatal outcomes after premature rupture of the membranes; tocolytics for premature labor; and oxytocin, ergot alkaloids, and prostaglandin analogues for postpartum hemorrhage. The fetal and neonatal effects of therapy for the conditions that occur during labor and delivery are usually benign, but significant morbidity and mortality involving the mother, the fetus, and the newborn are ever-present risks.

CONCLUSION

Awareness of the conditions and complications requiring drug therapy during labor and delivery will allow hospital pharmacists to make knowledgeable decisions about the rapid accessibility of critical medications in the labor and delivery unit.

Tocolysis for repeat external cephalic version in breech presentation at term: a randomised, double-blinded, placebo-controlled trial

BACKGROUND

External cephalic version (ECV) reduces the incidence of breech presentation at term and caesarean section for non-cephalic births. Tocolytics may improve success rates, but are time consuming, may cause side effects and have not been proven to alter caesarean section rates. The aim of this trial was to determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt.

OBJECTIVE

To determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt.

DESIGN

Randomised, double-blinded, placebo-controlled trial.

SETTING

UK teaching hospital.

POPULATION

One hundred and twenty-four women with a breech presentation at term who had undergone an unsuccessful attempt at ECV.

METHODS

Relative risks with 95% confidence intervals for categorical variables and a t test for continuous variables. Analysis was by intention to treat.

MAIN OUTCOME MEASURES

Incidence of cephalic presentation at delivery. Secondary outcomes were caesarean section and measures of neonatal and maternal morbidity.

RESULTS

The use of tocolysis for a repeat attempt at ECV significantly increases the incidence of cephalic presentation at delivery (RR 3.21; 95% CI 1.23-8.39) and reduces the incidence of caesarean section (RR 0.33; 95% CI 0.14-0.80). The effects were most marked in multiparous women (RR for cephalic presentation at delivery 9.38; 95% CI 1.64-53.62). Maternal and neonatal morbidity remain unchanged.

CONCLUSIONS

The use of tocolysis increases the success rate of repeat ECV and reduces the incidence of caesarean section. A policy of only using tocolysis where an initial attempt has failed leads to a relatively high success rate with minimum usage of tocolysis.

What’s new and novel in obstetric anesthesia? Contributions from the 2003 scientific literature

THE PREGNANT PATIENT: Age; maternal disease; prophylactic antibiotics; gastroesophageal reflux; obesity; starvation; genotyping; coagulopathy; infection; substance abuse; altered drug responses in pregnancy; physiological changes of pregnancy. THE FETUS: Fetal monitoring; intrauterine surgery. THE NEWBORN: Breastfeeding; maternal infection, fever, and neonatal sepsis evaluation. OBSTETRIC COMPLICATIONS: Embolic phenomena; hemorrhage; preeclampsia; preterm delivery. OBSTETRIC MANAGEMENT: External cephalic version and cervical cerclage; elective cesarean delivery; fetal malpresentation; vaginal birth after cesarean delivery; termination of pregnancy. OBSTETRIC ANESTHESIA: Analgesia for labor and delivery; anesthesia for cesarean delivery; anesthesia for short obstetric operations; complications of anesthesia. MISCELLANEOUS: Consent; ethics; history; labor support; websites/books/leaflets/journal announcements.

Randomized comparison of intravenous nitroglycerin and subcutaneous terbutaline for external cephalic version under tocolysis

OBJECTIVE

The purpose of this study was to compare the efficacy and safety of intravenous nitroglycerin with that of subcutaneous terbutaline as a tocolytic agent for external cephalic version at term.

STUDY DESIGN

We performed a prospective randomized trial. Patients between 37 and 42 weeks of gestation were assigned randomly to receive either 200 microg of intravenous nitroglycerin therapy or 0.25 mg of subcutaneous terbutaline therapy for tocolysis during external cephalic version. The rate of successful external cephalic version and side effects were compared between groups.

RESULTS

Of 59 randomly assigned patients, 30 patients received intravenous nitroglycerin, and 29 patients received subcutaneous terbutaline. The overall success rate of external cephalic version in the study was 39%. The rate of successful external cephalic version was significantly higher in the terbutaline group (55% vs 23%; P = .01). The incidence of palpitations was significantly higher in patients who received terbutaline therapy (17.2% vs 0%; P = .02), as was the mean maternal heart rate at multiple time periods.

CONCLUSION

Compared with intravenous nitroglycerin, subcutaneous terbutaline was associated with a significantly higher rate of successful external cephalic version 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.