Intramuscular oxytocin versus Syntometrine® versus carbetocin for prevention of primary postpartum haemorrhage after vaginal birth: a randomised double-blinded clinical trial of effectiveness, side effects and quality of life

Effectiveness of prophylactic carbetocin versus oxytocin following vaginal delivery for preventing severe postpartum hemorrhage

OBJECTIVE

To compare the effectiveness of prophylactic carbetocin with prophylactic oxytocin for preventing severe postpartum hemorrhage (PPH) following vaginal delivery.

METHODS

This before and after cohort study took place between 2020 and 2021 in a university maternity hospital. In 2021, the protocol for PPH prevention immediately after vaginal delivery changed: intravenous oxytocin (5 IU) was replaced by intravenous carbetocin (100 μg). All patients with vaginal births were included, with two groups compared: patients who received prophylactic oxytocin in 2020 and those who received prophylactic carbetocin in 2021. The primary outcome was severe PPH, defined as one or more of the following: estimated blood loss ≥1500 mL, transfusion ≥4 units of red blood cells, Bakri balloon use, embolization, vascular ligation, hysterectomy, and maternal death.

RESULTS

Among 4832 women included, 2417 received oxytocin and 2415 received carbetocin. The rate of severe PPH was similar in both groups (0.5% vs. 0.6%, respectively; adjusted odds ratio, 0.8 [95% confidence interval, 0.4-1.8]). The rate of PPH ≥500 mL was lower in the carbetocin group (4% vs. 5.8%; P = 0.004).

CONCLUSION

Although prophylactic carbetocin was associated with a reduction in the rate of PPH ≥500 mL, carbetocin is no different to oxytocin in preventing severe PPH caused by atony after vaginal delivery.

The Role of Thromboelastography during the Management of Postpartum Hemorrhage: Background, Evidence, and Practical Application

Postpartum hemorrhage (PPH) is a common cause of significant maternal morbidity and mortality that can be associated with coagulopathy, especially hypofibrinogenemia. There is interest in point-of-care viscoelastic hemostatic assays (POC-VHA) in PPH because prompt knowledge of coagulation status can aid diagnosis, identify cases of severe coagulopathy, and allow ongoing monitoring during rapid bleeding. The incidence of coagulopathy in most cases of PPH is low because of the procoagulant state of pregnancy, including raised fibrinogen levels of around 4 to 6 g/L. A Clauss fibrinogen of >2 g/L or POC-VHA equivalent has been found to be adequate for hemostasis during PPH. POC-VHA has been used successfully to diagnose hypofibrinogenemia (Clauss fibrinogen of ≤2 g/L) and guide fibrinogen treatment which has reduced bleed size and complications of massive transfusion. There are uncertainties about the use of POC-VHA to direct fresh frozen plasma and platelet administration during PPH. Several POC-VHA algorithms have been used successfully incorporated in the management of many thousands of PPHs and clinicians report that they are easy to use, interpret, and aid decision making. Due to the relative cost of POC-VHA and lack of definitive data on improving outcomes, these devices have not been universally adopted during PPH.

Exploring cardiac effects after oxytocin 2.5 IU or carbetocin 100 μg: A randomised controlled trial in women undergoing planned caesarean delivery

BACKGROUND

Oxytocin can stimulate release of myocardial biomarkers troponin I and T, prolong QTc and induce ST-depression.

OBJECTIVE

To explore cardiac changes after either intravenous carbetocin or oxytocin.

STUDY DESIGN

Exploratory phase 4 randomised controlled trial.

SETTING

Obstetrics units of Oslo University Hospital, Norway between September 2015 and May 2018.

PARTICIPANTS

Forty healthy, singleton pregnant women aged 18 to 50 years at gestational age at least 36 weeks with a planned caesarean delivery.

INVENTIONS

Participants were randomised to receive either oxytocin 2.5 IU or carbetocin 100 μg immediately after delivery.

MAIN OUTCOME MEASURES

The primary endpoint was the assessment of troponin I within 48 h of study drug administration. Troponin I and T, and creatine kinase myocardial band assessments were measured before spinal anaesthesia (baseline), and again at 4, 10 and 24 h after delivery. QTc, ST-depression and relative increase in heart rate were recorded from start of study drug administration to 10 min after delivery. All adverse events were monitored.

RESULTS

Compared with the carbetocin group, higher troponin I levels were observed in the oxytocin group at 4 h and 10 h after delivery. For both treatment groups, an increase from baseline in troponin I and T was most pronounced at 10 h after delivery, and it had begun to decline by 24 h. QTc increased with time after administration of both study drugs, with a mean maximum increase of 10.4 ms observed at 9 min (P  < 0.001). No statistical differences were observed in QTc (P = 0.13) or ST-depression (P = 0.11) between the treatment groups.

CONCLUSIONS

Oxytocin 2.5 IU and carbetocin 100 μg caused a similar increase in QTc. The trial was underpowered with regards to ST-depression and the release of myocardial biomarkers and these warrant further investigation. Data from this trial will inform a larger phase 4 trial to determine potential drug differences in troponin release.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02528136.

Is there a role for carbetocin in the prophylaxis of postpartum obstetric haemorrhage?

Postpartum haemorrhage is a common complication of pregnancy, most commonly due to uterine atony. Uterotonics have a vital role in preventing postpartum haemorrhage but the choice of the most effective agent with the fewest adverse effects is a subject of debate. Carbetocin, a synthetic analogue of oxytocin has been available in the UK since 2007 but is not currently widely used. It has a longer duration of action than oxytocin, which avoids the need for an infusion and as it is heat-stable it can be stored at room temperature. Current UK clinical guidelines, based on the results of older meta-analyses, do not recommend carbetocin as a first-line agent. A Cochrane review, published in 2018, ranked carbetocin in the top three drug regimens for preventing postpartum haemorrhage and an international consensus statement on uterotonic use for caesarean birth concluded that carbetocin may become the preferred drug for caesarean birth, by reducing the need for additional uterotonics. The higher cost of carbetocin when compared with oxytocin is a limiting factor, but the significant healthcare costs of a postpartum haemorrhage and the physiological impact of this event suggests it a reasonable alternative to consider, especially if ergometrine is contraindicated or in those who are undergoing a caesarean birth or are at high risk of bleeding.

Effect of Carbetocin on Postpartum Hemorrhage after Vaginal Delivery: A Meta-Analysis

Background

The efficacy of oxytocin and carbetocin in preventing postpartum hemorrhage (PPH) in women with vaginal delivery has been controversial. This study is aimed at conducting a meta-analysis that compares the efficacy of carbetocin and oxytocin in the prevention of PPH among women with vaginal delivery.

Methods

Literature was retrieved from PubMed, Medline, Embase, CENTRAL, and CNKI databases. The randomized controlled trials (RCTs) that compare the efficacy of carbetocin and oxytocin to prevent PPH were searched. Data from the included literatures were extracted by two researchers, including author, title, publication date, study type, study number, the incidence of PPH, number of patients requiring additional uterotonics, and number of patients requiring blood transfusion. Jadad scale was used to evaluate the quality of the included RCTs. The Chi-square test was adopted for the heterogeneity test. A fixed-effect model was used for analysis if heterogeneity did not exist between literatures. If heterogeneity exists between literatures, a random-effect model was used for analysis. The source of heterogeneity was explored by subgroup analysis and sensitivity analysis.

Results

The incidence of PPH in the carbetocin group was lower than that in the oxytocin group (OR = 0.62, 95% CI (0.46, 0.84), Z = 3.14, P = 0.002). There was no heterogeneity among studies (χ² = 7.29, P = 0.12, I² = 45%) and no significant publication bias (P > 0.05). The proportion of women requiring additional uterotonics in the carbetocin group was lower than that in the oxytocin group (OR = 0.41, 95% CI (0.29, 0.56), Z = 5.34, P < 0.00001). There was no heterogeneity among studies (χ² = 0.82, P = 0.84, I² = 0%) and no significant publication bias (P > 0.05). There was no significant difference in the proportion of women needing blood transfusion between the carbetocin group and the oxytocin group (OR = 0.92, 95% CI (0.66, 1.29), Z = 0.46, P = 0.64). There was no heterogeneity among studies (χ² = 3.06, P = 0.55, I² = 0%) and no significant publication bias (P > 0.05).

Conclusion

Carbetocin is superior to oxytocin in preventing PPH among women with vaginal delivery and can be widely used in clinical practice.