Pragmatic comparison of β2-agonist side effects within the Worldwide Atosiban versus Beta Agonists Study

Comparison of terbutaline and atosiban as tocolytic agents in intrauterine repair of myelomeningocele: a retrospective cohort study

BACKGROUND

Myelomeningocele (MMC) is a neural tube defect disease. Antenatal repair of fetal MMC is an alternative to postnatal repair. Many agents can be used as tocolytics during the in utero fetal repair such as β2-agonists and oxytocin receptor antagonists, with possible maternal and fetal repercussions. This study aims to compare maternal arterial blood gas analysis between terbutaline or atosiban, as tocolytic agents, during intrauterine MMC repair.

METHODS

Retrospective cohort study. Patients were divided into two groups depending on the main tocolytic agent used during intrauterine MMC repair: atosiban (16) or terbutaline (9). Maternal arterial blood gas samples were analyzed on three moments: post induction (baseline, before the start of tocolysis), before extubation, and two hours after the end of the surgery.

RESULTS

Twenty-five patients were included and assessed. Before extubation, the terbutaline group showed lower arterial pH (7.347 ± 0.05 vs. 7.396 ± 0.02 for atosiban, p = 0.006) and higher arterial lactate (28.33 ± 12.76 mg.dL-1 vs. 13.06 ± 6.35 mg.dL-1, for atosiban, p = 0.001) levels.

CONCLUSIONS

Patients who received terbutaline had more acidosis and higher levels of lactate, compared to those who received atosiban, during intrauterine fetal MMC repair.

Appraisal of trimester-specific fetal heart rate and its role in gestational age prediction

INTRODUCTION

The aim of this study was to evaluate and report normal sonographic FHR values among low-risk singleton women across the three trimesters of pregnancy and determine FHR role in gestational age prediction.

METHOD

A prospective cross-sectional study of 2727 low-risk singleton pregnant women was undertaken. FHR measurements were obtained by a consultant radiologist and three experienced sonographers using transabdominal approach from January 2019 to December 2020. Two FHR measurements were taken for each participant. The fetal lie and presentation were also documented in the first trimester. Data were analysed using SPSS version 24 (IBM, Armonk, NY, USA).

RESULT

The maternal mean ± SD age was 25.8 ± 6.5 years and mean FHR for first, second and third trimesters were 151 ± 16, 145 ± 6 and 125±6 bpm respectively. The mean ± SD gestational age were 10 ± 2, 19 ± 3 and 34 ± 2 weeks for the first, second and third trimester respectively. Using ANOVA, there were statistically significant differences in FHR across the three trimesters (p ≤ 0.05). A positive correlation existed between maternal age and FHR (r = 0.57, p ≤ 0.05).

CONCLUSION

This study has established normal values for FHR in first, second and third trimester respectively. Referring physicians, radiologists, sonographers, obstetricians and gynaecologists may consider FHR of (135-167) bpm (139-151) bpm and (119-131) bpm as normal FHR ranges for the first, second and third trimester respectively. This study has also revealed the possibility of gestational age prediction using FHR with the equation [Gestational Age = 87.8 - (0.47) FHR].

IMPLICATIONS FOR PRACTICE

This paper provides the most up-to-date sonographic FHR recommendations for fetal management. More importantly, findings from this study also suggests that ultrasound practitioners can use FHR measurements as a reliable alternative for fetal dating.

Comparison of perinatal outcomes between long-term and short-term use of tocolytic agent: a historical cohort study in a single perinatal hospital

AIM

The aim of this study was to evaluate the effect of long-term use of tocolytic agents to prevent preterm delivery and improve perinatal outcome.

METHODS

A historical cohort study was performed in a single perinatal center. The maternal characteristics, frequency of preterm labor and prescribed dose of tocolytic agents were compared before and after changing the management protocol for threatened premature delivery.

RESULTS

A total of 1548 deliveries were carried out before changing the protocol for the use of tocolytic agents for threatened premature delivery and 1444 deliveries afterwards. There was no significant difference in the maternal characteristics before and after the revision except for maternal age. The total number of ritodrine hydrochloride ampules used was reduced from 4654 to 514, and the total vials of magnesium sulfate used were reduced from 1574 to 193, but perinatal outcomes, such as rate of preterm birth, neonatal weight, and rate of NICU hospitalization were not different between the groups.

CONCLUSION

There was no significant change in the frequency of preterm delivery before and after changing of the protocol for threatened premature delivery. Because a decrease in the given dose of tocolytic agents did not affect the timing of delivery and neonatal outcomes, long-term tocolysis in patients with threatened premature delivery should be restricted to prevent maternal and fetal adverse side-effects.

The effects of oxytocin and atosiban on the modulation of heart rate in pregnant women

OBJECTIVE

To evaluate autonomic modulation of heart rate in pregnant women treated with oxytocin to induce labor and with atosiban (an oxytocin antagonist) to arrest preterm labor.

METHODS

A prospective study with two cohorts: 14 pregnant women treated with atosiban for premature uterine contractions, and 28 women undergoing induction of labor with oxytocin. Computerized analyses of the electrocardiogram were performed with spectral and nonlinear dynamic analyses.

RESULTS

Atosiban did not alter any of the variables associated with heart rate variability, whereas oxytocin showed a dose-dependent decrease in heart rate (p < 0.05) and a significant increase in all spectral variables studied (p < 0.01).

CONCLUSIONS

Atosiban has no adverse effects on the cardiovascular system or the modulation of heart rate. Oxytocin, on the other hand, can cause a dose-dependent bradycardic effect and an increase in the spectral power, thus should be used with caution in certain pregnant women.

Fetal heart rate regresses toward the mean in the third trimester

The purpose of this study was to investigate the feasibility of different fetal heart rate (FHR) ranges in the nonstress test (NST) and to better understand the meaning of mild bradycardia and/or tachycardia without non-reassuring patterns. We employed the heredity to show that mild bradycardia (100-119 beats per minute, bpm) and mild tachycardia (161-180 bpm) regressed to the normal FHR range (120-160 bpm). We used linear regression to analyze FHR data from FHR tracings recorded 10 min before (NST, as the predictor) and 10 min after vibroacoustic stimulation testing (as the dependent variable). Acceleration for 15 bpm-15 seconds (Acc1515) and deceleration for 15 bpm-15 seconds (Dec1515) in the NST were also analyzed for each group. The slope of the best-fit line was the largest in the mild bradycardia group and the smallest in the normal range group. Dec1515 was most prominent in mild tachycardia and both the mild bradycardia and tachycardia groups regressed towards the mean FHR range. Therefore, we propose that both mild bradycardia and tachycardia of FHR in non-acute situations (range between 100 and 180 bpm) are not regarded a pathologic signal for clinical use.

Different effects of tocolytic medication on blood pressure and blood pressure amplification

BACKGROUND

The importance of tocolysis has been discussed extensively. Beta-2 adrenoceptor agonistic drugs like ritodrine have been the reference tocolytic drugs in most countries. Cardiovascular side-effects are frequent. Atosiban, a newer tocolytic drug, is a competitive antagonist of oxytocin and has fewer cardiovascular side effects. Although large studies exist, there is mainly subjective reporting of adverse reactions with a focus on blood pressure data.

OBJECTIVES

Evaluation of the acute effects of therapeutic doses of ritodrine and atosiban in comparison to placebo on central and peripheral blood pressures, central-to-peripheral blood pressure amplification and the augmentation index (AIx) in healthy non-pregnant female volunteers.

METHODS

A double-blind, randomized, crossover trial was carried out in 20 healthy non-pregnant female volunteers. Hemodynamic measurements were performed under standardized conditions.

RESULTS

At steady state, central and peripheral pressures did not differ from placebo in the atosiban group. During ritodrine -infusion, central SBP increased by 11% versus placebo (p = 0.012) and peripheral SBP by 10% (p = 0.004). In contrast to atosiban and placebo, blood pressure amplification was absent in the ritodrine group. While the AIx did not change in the atosiban group, with ritodrine, the AIx tended to decrease.

CONCLUSIONS

The present study shows the significant effects of ritodrine on the cardiovascular system. Atosiban has no significant effects and may be an appropriate alternative to tocolyticum, particularly in cardiovascularly complicated pregnancies.

Atosiban vs. ritodrine as a tocolytic in external cephalic version at term: a prospective cohort study

OBJECTIVE

To compare the success rate of external cephalic version (ECV) at term using ritodrine or atosiban as a tocolytic agent.

STUDY DESIGN

Prospective cohort study with a sample of 236 pregnant women with a breech presentation at term, from November 2006 to March 2008. Data have been analyzed from the moment the cephalic version is performed until the time of delivery.

RESULTS

ECV success rate using ritodrine as a tocolytic agent was 56.8% compared to 31.4% with atosiban. Ritodrine increases the version success potential more significantly than atosiban (P<0.05). In both cases, the use of ECV reduced the rate of cesarean sections, although a higher number of versions are required with atosiban [numbers needed to treat (NNT)=9.08] to avoid a cesarean section compared to ritodrine (NNT=3.41).

CONCLUSIONS

Ritodrine seems better than atosiban as tocolytic agent for ECVs.

Atosiban versus betamimetics in the treatment of preterm labour in Germany: an economic evaluation

BACKGROUND

The use of tocolytics is central in delaying birth; however, therapeutic options vary in effectiveness and adverse events profiles, which in turn could have consequences for medical resource use and cost of treatment. Betamimetics are commonly used tocolytic agents, but their mechanism of action affects multiple organ systems leading to numerous adverse events. The availability of an oxytocin receptor antagonist, specific for prevention of preterm labour, offers a treatment option that merits further evaluation. We aimed to compare economic implications of tocolysis using atosiban and betamimetics, considering treatment efficacy and safety, as well as cost consequences of treatment of associated adverse events.

METHODS

A systematic literature review identified six randomised clinical trials, three of them double-blinded, comparing atosiban with betamimetics, in which tocolysis was initiated within 48 hours of admission. Cost of drug treatment was calculated based on trial protocols and German hospital drug purchase costs. G-DRG Grouper was used to obtain cost per case. The drug regimen was concordant with the German guidelines for the management of preterm labour, with two alternative modalities of fenoterol analysed: continuous or bolus administrations.

RESULTS

According to the results of the meta-analysis of the three double-blinded, placebo-controlled clinical trials, atosiban and betamimetics have similar efficacy (RR = 0.99, 95%CI:0.94-1.04, p = 0.772). Compared to betamimetics, use of atosiban was associated with a significantly lower frequency of adverse events for tachycardia, palpitation, vomiting, headache, hyperglycaemia, tremor, dyspnoea, chest pain, hypocalemia and foetal tachycardia. In our economic analysis, cost savings from using atosiban versus continuous, or bolus, fenoterol was 423euro per patient from the payer's perspective. From the hospital's perspective, savings from using atosiban versus continuous fenoterol ranged from 259euro for 18 hours of tocolysis to 105euro for 48 hours; the respective values for bolus fenoterol were 244euro and 55euro. In the probabilistic sensitivity analysis atosiban was cost saving versus both continuous and bolus fenoterol in 87%-100% of scenarios.

CONCLUSION

In a German setting, atosiban is cost saving versus betamimetics in the treatment of preterm labour from the payer, hospital and combined perspectives. Cost savings stem from the superior safety profile of atosiban.