Carbetocin versus oxytocin for prevention of postpartum hemorrhage in obese nulliparous women undergoing emergency cesarean delivery

The minimum effective dose (ED90) of prophylactic oxytocin infusion during cesarean delivery in patients with and without obesity: an up-down sequential allocation dose-response study

BACKGROUND

Obesity is associated with greater oxytocin requirement during labor induction or augmentation. There are scant data exploring the intra-operative requirement during cesarean delivery in patients with obesity, and none comparing it with those without obesity. We evaluated the minimum effective dose (ED90) of an oxytocin infusion to achieve adequate uterine tone during cesarean delivery in patients with and without obesity.

METHODS

Patients (body mass index ≥30 kg/m2 represented patients with obesity) undergoing cesarean delivery using subarachnoid block were included. This prospective dual-arm dose-finding study used a 9:1 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h at cord clamping in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician four minutes after initiation of the infusion. The dose of oxytocin infusion for subsequent patients was determined according to the response of the previous patient in the group. Oxytocin-associated side effects were evaluated. Dose-response data for the groups was evaluated using log-logistic function and ED90 estimates derived from fitted equations using the delta method.

RESULTS

The ED90 of oxytocin was significantly higher for patients with obesity (n = 40) compared with those without obesity (n = 40) [25.7 IU/h, 95% CI 18.6 to 32.9) vs. 16.6 IU/h, 95% CI 14.9 to 18.3)]; relative ratio 1.55 [95% CI 1.09 to 2.01] (P = 0.019).

CONCLUSIONS

Patients with obesity require a higher intra-operative oxytocin infusion dose rate to achieve a satisfactorily contracted uterus after fetal delivery when compared with patients without obesity.

Peripherally restricted oxytocin is sufficient to reduce food intake and motivation, while CNS entry is required for locomotor and taste avoidance effects

OBJECTIVES

Oxytocin (OT) has a well-established role in reproductive behaviours; however, it recently emerged as an important regulator of energy homeostasis. In addition to central nervous system (CNS), OT is found in the plasma and OT receptors (OT-R) are found in peripheral tissues relevant to energy balance regulation. Here, we aim to determine whether peripheral OT-R activation is sufficient to alter energy intake and expenditure.

METHODS AND RESULTS

We first show that systemic OT potently reduced food intake and food-motivated behaviour for a high-fat reward in male and female rats. As it is plausible that peripherally, intraperitoneally (IP) injected OT crosses the blood-brain barrier (BBB) to produce some of the metabolic effects within the CNS, we screened, with a novel fluorescently labelled-OT (fAF546-OT, Roxy), for the presence of IP-injected Roxy in CNS tissue relevant to feeding control and compared such with BBB-impermeable fluorescent OT-B₁₂ (fCy5-OT-B_12; BRoxy). While Roxy did penetrate the CNS, BRoxy did not. To evaluate the behavioural and thermoregulatory impact of exclusive activation of peripheral OT-R, we generated a novel BBB-impermeable OT (OT-B₁₂ ), with equipotent binding at OT-R in vitro. In vivo, IP-injected OT and OT-B₁₂ were equipotent at food intake suppression in rats of both sexes, suggesting that peripheral OT acts on peripheral OT-R to reduce feeding behaviour. Importantly, OT induced a potent conditioned taste avoidance, indistinguishable from that induced by LiCl, when applied peripherally. Remarkably, and in contrast to OT, OT-B₁₂ did not induce any conditioned taste avoidance. Limiting the CNS entry of OT also resulted in a dose-dependent reduction of emesis in male shrews. While both OT and OT-B₁₂ proved to have similar effects on body temperature, only OT resulted in home-cage locomotor depression.

CONCLUSIONS

Together our data indicate that limiting systemic OT CNS penetrance preserves the anorexic effects of the peptide and reduces the clinically undesired side effects of OT: emesis, taste avoidance and locomotor depression. Thus, therapeutic targeting of peripheral OT-R may be a viable strategy to achieve appetite suppression with better patient outcomes.

[The cesarean procedure: Guidelines for clinical practice from the French College of Obstetricians and Gynecologists]

OBJECTIVE

To identify procedures to reduce maternal morbidity during cesarean.

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE® method with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane and EMBASE databases. The quality of the evidence was assessed (high, moderate, low, very low) and a (i) strong or (ii) weak recommendations or (iii) no recommendation were formulated. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Of the 27 questions, there was agreement between the working group and the external reviewers on 26. The level of evidence of the literature was insufficient to provide a recommendation on 15 questions. Preventing hypothermia is recommended to increase maternal satisfaction and comfort (weak recommendation) and to reduce neonatal hypothermia (strong recommendation). The quality of the evidence of the literature did not allow to recommend the skin disinfectant to be used nor the relevance of a preoperative vaginal disinfection nor the choice between the use or nonuse of an indwelling bladder catheterization (if micturition takes place 1 hour before the cesarean section). The Misgav-Ladach technique or its analogues should be considered rather than the Pfannenstiel technique to reduce maternal morbidity (weak recommendation) bladder flap before uterine incision should not be performed routinely (weak recommendation), but a blunt (weak recommendation) and cephalad-caudad extension of uterine incision (weak recommendation) should be considered to reduce maternal morbidity. Antibiotic prophylaxis is recommended to reduce maternal infectious morbidity (strong recommendation) without recommendation on its type or the timing of administration (before incision or after cord clamping). The administration of carbetocin after cord clamping does not significantly decrease the incidence of blood loss>1000 ml, anemia, or blood transfusion compared with the administration of oxytocin. Thus, it is not recommended to use carbetocin rather than oxytocin in cesarean. It is recommended that systematic manual removal of the placenta not to be performed (weak recommendation). An antiemetic should be administered after cord clamping in women having a planned cesarean under locoregional anaesthesia to reduce intraoperative and postoperative nausea and vomiting (strong recommendation) with no recommendation regarding choice of use one or two antiemetics. The level of evidence of the literature was insufficient to provide any recommendation concerning single or double-layer closure of the uterine incision, or the uterine exteriorization. Closing the peritoneum (visceral or parietal) should not be considered (weak recommendation). The quality of the evidence of the literature was not sufficient to provide recommendation on systematic subcutaneous closure, including in obese or overweight patients, or the use of subcuticular suture in obese or overweight patients. The use of subcuticular suture in comparison with skin closure by staples was not considered as a recommendation due to the absence of a consensus in the external review rounds.

CONCLUSION

In case of cesarean, preventing hypothermia, administering antiemetic and antibiotic prophylaxis after cord clamping are the only strong recommendations. The Misgav-Ladach technique, the way of performing uterine incision (no systematic bladder flap, blunt cephalad-caudad extension), not performing routine manual removal of the placenta nor closure of the peritoneum are weak recommendations and may reduce maternal morbidity.

Implementing Heat-Stable Carbetocin for Postpartum Haemorrhage Prevention in Low-Resource Settings: A Rapid Scoping Review

Heat-stable carbetocin (HSC), a long-acting oxytocin analogue that does not require cold-chain transportation and storage, is effective in preventing postpartum haemorrhage (PPH) in vaginal and caesarean deliveries in tertiary-care settings. We aimed to identify literature documenting how it is implemented in resource-limited and lower-level maternity care settings to inform policies and practices that enable its introduction in these contexts. A rapid scoping review was conducted with an 8-week timeframe by two reviewers. MEDLINE, EMBASE, Emcare, the Joanna Briggs Institute Evidence-Based Practice Database, the Maternity and Infant Care Database, and the Cochrane Library were searched for publications in English, French, and Spanish from January 2011 to September 2021. Randomized and non-randomized studies examining the feasibility, acceptability, and health system considerations in low-income and lower-middle-income countries were included. Relevant data were extracted using pretested forms, and results were synthesized descriptively. The search identified 62 citations, of which 12 met the eligibility criteria. The review did not retrieve studies focusing on acceptability and health system considerations to inform HSC implementation in low-resource settings. There were no studies located in rural or lower-level maternity settings. Two economic evaluations concluded that HSC is not feasible in terms of cost-effectiveness in lower-middle-income economies with private sector pricing, and a third one found superior care costs in births with PPH than without. The other nine studies focused on demonstrating HSC effectiveness for PPH prevention in tertiary hospital settings. There is a lack of evidence on the feasibility (beyond cost-effectiveness), acceptability, and health system considerations related to implementing HSC in resource-constrained and lower-level maternity facilities. Further implementation research is needed to help decision-makers and practitioners offer an HSC-inclusive intervention package to prevent excessive bleeding among pregnant women living in settings where oxytocin is not available or of dubious quality.

Effectiveness and safety of carboxytocin versus oxytocin in preventing postpartum hemorrhage: A systematic review and meta-analysis

OBJECTIVE

This study compared the effectiveness and safety of carbetocin and oxytocin in preventing postpartum hemorrhage (PPH).

METHODS

A systematic literature search was performed on PubMed, Embase, and the Cochrane Library for relevant studies published up to February 2019. Next, two independent reviewers screened the studies according to the selection criteria as well as the strategies recommended by the Cochrane Collaboration. Data were then extracted and evaluated. All statistical analyses were performed using RevMan 5.1.

RESULTS

A total of 24 studies involving 37 383 patients were included for analysis. For cesarean section patients, carbetocin was superior to oxytocin in reduction of the need for additional uterine contraction (odds ratio [OR] = 0.48, 95% confidence interval [CI] [0.35, 0.65], p < 0.00001), PPH (OR = 0.70, 95% CI [0.51, 0.95], p = 0.02), blood loss (mean [MD] = -64.36, 95% CI [-107.78, -20.93], p = 0.004), and transfusion (OR = 0.59, 95% CI [0.42, 0.82], p = 0.002), and there was no significant difference in severe PPH (OR = 0.84, 95% CI [0.66, 1.090], p = 0.19). For vaginal delivery patients, carbetocin was superior to oxytocin in reduction of the need for additional uterine contractions (OR = 0.48, 95% CI [0.25, 0.93], p = 0.03), PPH (OR = 0.28, 95% CI [0.09, 0.91], p = 0.03), and blood loss (MD = -63.52, 95% CI [-113.43, -13.60], p = 0.01), and there were no significant differences in severe PPH (OR = 0.82, 95% CI [0.40, 1.69], p = 0.59) and transfusion (OR = 0.60, 95% CI [0.22, 1.61], p = 0.31). With regard to safety, for cesarean section patients, carbetocin was superior to oxytocin in reduction of the incidence of headache (OR = 0.72, [0.55, 0.95], p = 0.02), and there were no significant differences in nausea, vomiting, abdominal pain, flushing, tremors, itching, dizziness, and fever. For vaginal delivery patients, there were no significant differences in nausea, vomiting, headache, abdominal pain, flushing, tremors, itching, dizziness, and fever between the two drugs.

CONCLUSION

For patients undergoing cesarean section and vaginal delivery, carbetocin was superior to oxytocin in effectiveness and similar in safety. Therefore, carbetocin is expected to be an alternative uterine contraction agent for preventing PPH.

Preventing postpartum hemorrhage after cesarean delivery: a network meta-analysis of available pharmacologic agents

BACKGROUND

Postpartum hemorrhage causes a quarter of global maternal deaths. The World Health Organization recommends oxytocin as the first line agent to prevent hemorrhage during cesarean delivery. However, some randomized controlled trials suggest that other uterotonics are superior.

OBJECTIVE

We conducted a network meta-analysis comparing the ability of pharmacologic agents to reduce blood loss and minimize the need for additional uterotonics during cesarean delivery.

DATA SOURCES

We searched the Cochrane Central Register of Controlled Trials, Embase, and MEDLINE databases from inception to May 2020.

STUDY ELIGIBILITY CRITERIA

We included randomized controlled trials that compared oxytocin, carbetocin, misoprostol, ergometrine, carboprost, or combinations of these in the prevention of postpartum hemorrhage during cesarean delivery.

METHODS

We performed a systematic review followed by an NMA in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Quality of the evidence was assessed with the Confidence in Network Meta-Analysis approach and Grading of Recommendations, Assessment, Development and Evaluations tool within the summary of findings table. Our primary outcomes were the estimated blood loss and need for additional uterotonics. Secondary outcomes included nausea and postpartum hemorrhage of >1000 mL. We performed sensitivity analyses to explore the influence of surgical context and oxytocin administration strategy.

RESULTS

A total of 46 studies with 7368 participants were included. Of those, 21 trials (6 agents and 3665 participants) formed the "estimated blood loss" network and, considering the treatment effects, certainty in the evidence, and surface under the cumulative ranking curve scores, carbetocin was assessed to probably be superior to oxytocin, but only in reducing the estimated blood loss by a clinically insignificant volume (54.83 mL; 95% confidence interval, 26.48-143.78). Misoprostol, ergometrine, and the combination of oxytocin and ergometrine were assessed to probably be inferior, whereas the combination of oxytocin and misoprostol was assessed to definitely be inferior to oxytocin. A total of 37 trials (8 agents and 6193 participants) formed the "additional uterotonic" network and, again, carbetocin was assessed to probably be superior to oxytocin, requiring additional uterotonics 185 (95% confidence interval, 130-218) fewer times per 1000 cases. Oxytocin plus misoprostol, oxytocin plus ergometrine, and misoprostol were assessed to probably be inferior, whereas carboprost, ergometrine, and the placebo were definitely inferior to oxytocin. For both primary outcomes, oxytocin administration strategies had a higher probability of being the best uterotonic, if initiated as a bolus.

CONCLUSION

Carbetocin is probably the most effective agent in reducing blood loss and the need for additional uterotonics. Oxytocin appears to be more effective when initiated as a bolus.

Risk Factors for Carbetocin Failure after a Cesarean Section: Is Obesity One of Them?

Obese pregnant women have increased rates of fetal macrosomia, long labor, and cesarean sections, which lead to an increased risk of postpartum hemorrhage (PPH). Carbetocin is useful for the prevention of PPH after a cesarean section. Our study aimed to investigate predictors of carbetocin failure after a cesarean section, and specifically whether obesity is associated with carbetocin failure. We retrospectively analyzed all women who received carbetocin after a cesarean section. Carbetocin failure was defined as changes in hematocrit and hemoglobin, blood loss ≥ 1000 mL, and the need for an additional uterotonic agent or second-line therapies for persistent PPH. Univariate and multivariate analyses were performed to investigate predictors of carbetocin failure. The study included 600 women, with 131 (21.8%) obese women. Overall, 44 (7.3%) carbetocin failures were reported, and rates of obese women were similar between groups (carbetocin failure, 11.4% vs. 22.9%; p = 0.08). Previous PPH (p < 0.001), a cesarean section during labor (p = 0.01), cervical ripening (p = 0.02), and birthweight (p = 0.01) were significantly different between groups. In the multivariable logistic regression analysis adjusted for potential confounders, cervical ripening (adjusted odds ratio (OR) 2.23, 95% confidence interval (CI) 1.01–4.80), compared with spontaneous labor, was significantly associated with carbetocin failure. Obesity was not associated with carbetocin failure after cesarean sections.

Side-effects of carbetocin to prevent postpartum hemorrhage: A systematic review and meta-analysis of randomized controlled trials

Postpartum hemorrhage (PPH) increases the risk of maternal death worldwide. Heat-stable carbetocin, a long-acting oxytocin analog, is a newer uterotonic agent. Clinicians do not fully understand its side-effects, particularly the unanticipated side-effects. The aim of this study is to investigate the side-effects of carbetocin to PPH. The Cochrane Library, Web of Science, PubMed, Elsevier ScienceDirect, Embase, and ClinicalTrials.gov were searched from the inception to September 2020. Randomized controlled trials (RCTs) that considered pregnant women who received carbetocin before delivery and provided at least one adverse event were included. Statistical analysis included random or fixed-effect meta-analyses using relative risk. Stratified analyses and sensitivity analyses were also performed. Begger's and Egger's test and funnel plots were used to assess the publication bias. Seventeen RCTs involving 32,702 women were included, and all these studies ranked as medium- to high-quality. Twenty-four side-effects were reported. The use of carbetocin had a lower risk of vomiting in intravenously (0.53, 0.30 to 0.93) and cesarean birth (0.51, 0.32 to 0.81) women, and had a slightly higher risk of diarrhea (8.00, 1.02 to 62.79) compared with oxytocin intervention. No significant difference was found among other side-effects. Evidence from our systematic review and meta-analysis of 17 RCTs suggested that the risk of vomiting decreased with carbetocin use in the prevention of PPH after delivery.

THE EFFECT OF TRANEXAMIC ACID, CARBETOCIN AND ARGON PLASMA COAGULATION ON UTERINE INVOLUTION AFTER REPEAT CESAREAN SECTION

Repeat cesarean sections (CS) are associated with additional risks of perioperative complications. The aim of our study was ultrasound evaluation of uterine involution in women after repeat traditional cesarean delivery and after repeat CS using argon plasma coagulation and prophylactic use of tranexamic acid and carbetocin. Materials and methods. Prospective cohort study has been conducted on 140 patients who underwent second CS. Group I included 70 women who had repeat CS with the use of argon plasma coagulation and administration of 100 mcg carbetocin after cutting the umbilical cord. Ten minutes before the operation, 15 mg/kg of tranexamic acid was injected intravenously. Group II consisted of 70 women who had traditional CS, 10 IU dose of oxytocin, divided between 5 UI intravenous bolus dose and slow intravenous infusion, was administered after delivery of the baby. A serial ultrasonographic examination was carried out on the 2nd and 5th day of the postpartum period. Results. A study of the dynamics of changes in uterine body and uterine cavity volume revealed a faster rate of uterine cavity involution in group I compared with group II (p<0.05). In group I on the 5th day in comparison to the 2nd day the mean uterine body volume decreased by 27.75%, in group II – by 20.17%. In group I mean uterine cavity volume declined in three days by 21.09%, in group II – 14.22%. Uterine subinvolution was diagnosed in 3 (4,29%) cases in group I and in 19 (27,14%) cases in group II (p<0.05). Faster uterine involution in group I is probably associated with techniques, that were applied during intraoperative period. In addition, 2.86% (2 cases) from the group I versus 31.43% (22 cases) from the group II, needed additional uterotonic therapy after surgery (methylergometrine, misoprostol) (p<0.001). Conclusion. We have found differences in the course of uterine involution in women in group I in comparison with group II, such as significantly smaller uterine length on the 2nd and 5th day, significantly smaller uterine body and uterine cavity volume, faster rates of involution of the uterine cavity during the first 5 days of the postpartum period, thinner anterior uterine wall in the sutured area. We therefore conclude that complex use of tranexamic acid, carbetocin and argon plasma coagulation appears to be effective to maintain adequate uterine involution after repeat CS and prevent postoperative complications.

Uterotonic drugs to prevent postpartum haemorrhage: a network meta-analysis

BACKGROUND

Postpartum haemorrhage (PPH) is the leading cause of maternal mortality worldwide. Prophylactic uterotonic drugs can reduce blood loss and are routinely recommended. There are several uterotonic drugs for preventing PPH, but it is still debatable which drug or combination of drugs is the most effective.

OBJECTIVES

To identify the most effective and cost-effective uterotonic drug(s) to prevent PPH, and generate a ranking according to their effectiveness and side-effect profile.

METHODS

The Cochrane Pregnancy and Childbirth's Trials Register (1 June 2015), ClinicalTrials.gov and the World Health Organization (WHO)'s International Clinical Trials Registry Platform (ICTRP) were searched for unpublished trial reports (30 June 2015). In addition, reference lists of retrieved studies (updated October 2017) were searched for randomised trials evaluating uterotonic drugs for preventing PPH. The study estimated relative effects and rankings for preventing PPH, defined as blood loss of ≥ 500 ml and ≥ 1000 ml. Pairwise meta-analyses and network meta-analysis were performed to determine the relative effects and rankings of all available drugs and combinations thereof [ergometrine, misoprostol (Cytotec^®; Pfizer Inc., New York, NY, USA), misoprostol plus oxytocin (Syntocinon^®; Novartis International AG, Basel, Switzerland), carbetocin (Pabal^®; Ferring Pharmaceuticals, Saint-Prex, Switzerland), ergometrine plus oxytocin (Syntometrine^®; Alliance Pharma plc, Chippenham, UK), oxytocin, and a placebo or no treatment]. Primary outcomes were stratified according to the mode of birth, prior risk of PPH, health-care setting, drug dosage, regimen and route of drug administration. Sensitivity analyses were performed according to study quality and funding source, among others. A model-based economic evaluation compared the relative cost-effectiveness separately for vaginal births and caesareans with or without including side effects.

RESULTS

From 137 randomised trials and 87,466 women, ergometrine plus oxytocin, carbetocin and misoprostol plus oxytocin were found to reduce the risk of PPH blood loss of ≥ 500 ml compared with the standard drug, oxytocin [ergometrine plus oxytocin: risk ratio (RR) 0.69, 95% confidence interval (CI) 0.57 to 0.83; carbetocin: RR 0.72, 95% CI 0.52 to 1.00; misoprostol plus oxytocin: RR 0.73, 95% CI 0.6 to 0.9]. Each of these three strategies had 100% cumulative probability of being ranked first, second or third most effective. Oxytocin was ranked fourth, with an almost 0% cumulative probability of being ranked in the top three. Similar rankings were noted for the reduction of PPH blood loss of ≥ 1000 ml (ergometrine plus oxytocin: RR 0.77, 95% CI 0.61 to 0.95; carbetocin: RR 0.70, 95% CI 0.38 to 1.28; misoprostol plus oxytocin: RR 0.90, 95% CI 0.72 to 1.14), and most secondary outcomes. Ergometrine plus oxytocin and misoprostol plus oxytocin had the poorest ranking for side effects. Carbetocin had a favourable side-effect profile, which was similar to oxytocin. However, the analysis was restricted to high-quality studies, carbetocin lost its ranking and was comparable to oxytocin. The relative cost-effectiveness of the alternative strategies is inconclusive, and the results are affected by both the uncertainty and inconsistency in the data reported on adverse events. For vaginal delivery, when assuming no adverse events, ergometrine plus oxytocin is less costly and more effective than all strategies except carbetocin. The strategy of carbetocin is both more effective and more costly than all other strategies. When taking adverse events into consideration, all prevention strategies, except oxytocin, are more costly and less effective than carbetocin. For delivery by caesarean section, with and without adverse events, the relative cost-effectiveness is different, again because of the uncertainty in the available data.

LIMITATIONS

There was considerable uncertainty in findings within the planned subgroup analyses, and subgroup effects cannot be ruled out.

CONCLUSIONS

Ergometrine plus oxytocin, carbetocin and misoprostol plus oxytocin are more effective uterotonic drug strategies for preventing PPH than the current standard, oxytocin. Ergometrine plus oxytocin and misoprostol plus oxytocin cause significant side effects. Carbetocin has a favourable side-effect profile, which was similar to oxytocin. However, most carbetocin trials are small and of poor quality. There is a need for a large high-quality trial comparing carbetocin with oxytocin; such a trial is currently being conducted by the WHO. The relative cost-effectiveness is inconclusive, and results are affected by uncertainty and inconsistency in adverse events data.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015020005; Cochrane Pregnancy and Childbirth Group (substudy) reference number 0871; PROSPERO-Cochrane (substudy) reference number CRD42015026568; and sponsor reference number ERN_13-1414 (University of Birmingham, Birmingham, UK).

FUNDING

Funding for this study was provided by the National Institute for Health Research Health Technology Assessment programme in a research award to the University of Birmingham and supported by the UK charity Ammalife (UK-registered charity 1120236). The funders of the study had no role in study design, data collection, data synthesis, interpretation or writing of the report.

Carbetocin compared with oxytocin in non-elective Cesarean delivery: a systematic review, meta-analysis, and trial sequential analysis of randomized-controlled trials

PURPOSE

Carbetocin has been shown to reduce the requirement for additional uterotonics in women exclusively undergoing elective Cesarean delivery (CD). The aim of this review was to determine whether this effect could also be demonstrated in the setting of non-elective CD.

METHODS

Medline, Embase, CINAHL, Web of Science and Cochrane databases were searched for randomized-controlled trials (RCTs) in any language comparing carbetocin to oxytocin. Studies with data on women undergoing non-elective CD, where carbetocin was compared with oxytocin, were included. The primary outcome was the need for additional uterotonics. Secondary outcomes included incidence of blood transfusion, estimated blood loss (mL), incidence of postpartum hemorrhage (PPH; > 1000 mL) and mean hemoglobin drop (g·dL^-1 RESULTS: Five RCTs were included, with a total of 1,214 patients. The need for additional uterotonics was reduced with carbetocin compared with oxytocin (odds ratio, 0.30; 95% CI, 0.11 to 0.86; I², 90.60%). Trial sequential analysis (TSA) confirmed that the information size needed to show a significant reduction in the need for additional uterotonics had been exceeded. No significant differences were shown with respect to any of the secondary outcomes, but there was significant heterogeneity between the studies.

CONCLUSIONS

Carbetocin reduces the need for additional uterotonics in non-elective CD compared with oxytocin. TSA confirmed that this analysis was appropriately powered to detect the pooled estimated effect. Further trials utilizing consistent core outcomes are needed to determine an effect on PPH.

TRIAL REGISTRATION

PROSPERO CRD42019147256, registered 13 September 2019.

Carbetocin versus Oxytocin for the Prevention of Postpartum Hemorrhage in Cesarean Deliveries: A Retrospective Study of Two Consecutive Periods

Objective  The aim of the study is to investigate whether carbetocin prevents postpartum hemorrhage (PPH) more effectively than oxytocin Methods  This historical retrospective single-center cohort study compares women who underwent cesarean deliveries during two periods. During period A, oxytocin was used as a 10-unit bolus immediately after delivery, with 20 units thereafter infused for 24 hours. During period B, carbetocin in a single 100-µg injection replaced this protocol. The main outcome was PPH, defined as a decline in hemoglobin of more than 2 g/dL after the cesarean. The analysis was performed on the overall population and then stratified by the timing of the cesareans (before or during labor). A logistic regression analysis was performed. Results  This study included 1,796 women, 52% of whom had a cesarean before labor; 15% had a PPH. The crude PPH rate was lower in period B than in period A (13 vs. 17%, respectively, odds ratio 0.75, 95% confidence interval [CI]: 0.58-0.98). The difference was no longer significant in the multivariate analysis (adjusted odds ratio: 0.81, 95% CI 0.61-1.06). Results were similar when stratified by the timing of the cesareans (before or during labor). Conclusion  Carbetocin is not superior to oxytocin in preventing PPH. However, it does provide the advantage of requiring a single injection.

Carbetocin versus oxytocin for prevention of postpartum hemorrhage in hypertensive women undergoing elective cesarean section

OBJECTIVE

Assess the efficacy and safety of carbetocin, versus oxytocin in the prevention of postpartum hemorrhage in hypertensive women.

STUDY DESIGN

A randomized clinical trial.

SETTING

Obstetrics and Gynecology Department of Suez Canal University Hospital.

PATIENTS

One hundred and sixty hypertensive pregnant women who underwent CS.

INTERVENTIONS

Patients were randomized to receive either 10 IU oxytocin or 100 μg carbetocin. Primary outcomes included estimated blood loss, blood transfusion, hemoglobin (HB), and hematocrit changes pre- and post-delivery and the use of additional uterotonics.

RESULTS

The postoperative HB was not different from preoperative HB in the carbetocin group (11.8 ± 1.2 vs. 11.2 ± 1.2 g/dL) while it decreased significantly in the oxytocin group (12.1 ± 3.8 vs. 10.4 ± 1.1 g/dL, p < 0.001). Blood loss was significantly more among the oxytocin group (679.5 ± 200.25 vs. 424.75 ± 182.59 ml) in the carbetocin group (p < 0.001). Nausea, vomiting, and sweating were reported more significantly in oxytocin group patients.

CONCLUSION

Carbetocin was more effective than oxytocin in reducing intraoperative and postoperative blood loss.

A comparison of the efficacy of carbetocin and oxytocin on hemorrhage-related changes in women with cesarean deliveries for different indications

OBJECTIVE

To compare the efficacy of carbetocin and oxytocin on hemorrhage-related changes in women with cesarean deliveries (CS) for different indications.

MATERIALS AND METHODS

A retrospective cohort study was conducted on 1568 women with CS before labor onset (elective CS, n = 1153) or during labor (intrapartum CS, n = 415) after 24 weeks' gestation. We compared the fall in hemoglobin (Hb) and hematocrit (Hct) levels after CS, estimated blood loss, the need for additional uterotonic agents, blood transfusion, and the rate of postpartum hemorrhage between women with carbetocin and women with oxytocin treatment, stratified by indications for CS.

RESULTS

For women with elective CS, decreased Hb and Hct falls were noted with carbetocin treatment compared to oxytocin treatment in women with indications for prior CS, fetal malpresentation, and multiple gestation. The need for additional uterotonics was less in CS for prior CS, fetal malpresentation, and cephalopelvic disproportion and fewer transfusions in CS for multiple gestation in women with carbetocin compared to women with oxytocin treatment. For women with intrapartum CS, carbetocin was associated with decreased use of additional uterotonic agents and transfusion in CS for dysfunctional labor.

CONCLUSION

Carbetocin and oxytocin had differential effects on hemorrhage-related changes in women with CS for different indications.

Uterotonic agents for preventing postpartum haemorrhage: a network meta-analysis

BACKGROUND

Postpartum haemorrhage (PPH) is the leading cause of maternal mortality worldwide. Prophylactic uterotonic agents can prevent PPH, and are routinely recommended. The current World Health Organization (WHO) recommendation for preventing PPH is 10 IU (international units) of intramuscular or intravenous oxytocin. There are several uterotonic agents for preventing PPH but there is still uncertainty about which agent is most effective with the least side effects. This is an update of a Cochrane Review which was first published in April 2018 and was updated to incorporate results from a recent large WHO trial.

OBJECTIVES

To identify the most effective uterotonic agent(s) to prevent PPH with the least side effects, and generate a ranking according to their effectiveness and side-effect profile.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (24 May 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised controlled trials or cluster-randomised trials comparing the effectiveness and side effects of uterotonic agents with other uterotonic agents, placebo or no treatment for preventing PPH were eligible for inclusion. Quasi-randomised trials were excluded. Randomised trials published only as abstracts were eligible if sufficient information could be retrieved.

DATA COLLECTION AND ANALYSIS

At least three review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We estimated the relative effects and rankings for preventing PPH ≥ 500 mL and PPH ≥ 1000 mL as primary outcomes. Secondary outcomes included blood loss and related outcomes, morbidity outcomes, maternal well-being and satisfaction and side effects. Primary outcomes were also reported for pre-specified subgroups, stratifying by mode of birth, prior risk of PPH, healthcare setting, dosage, regimen and route of administration. We performed pairwise meta-analyses and network meta-analysis to determine the relative effects and rankings of all available agents.

MAIN RESULTS

The network meta-analysis included 196 trials (135,559 women) involving seven uterotonic agents and placebo or no treatment, conducted across 53 countries (including high-, middle- and low-income countries). Most trials were performed in a hospital setting (187/196, 95.4%) with women undergoing a vaginal birth (71.5%, 140/196).Relative effects from the network meta-analysis suggested that all agents were effective for preventing PPH ≥ 500 mL when compared with placebo or no treatment. The three highest ranked uterotonic agents for prevention of PPH ≥ 500 mL were ergometrine plus oxytocin combination, misoprostol plus oxytocin combination and carbetocin. There is evidence that ergometrine plus oxytocin (RR 0.70, 95% CI 0.59 to 0.84, moderate certainty), carbetocin (RR 0.72, 95% CI 0.56 to 0.93, moderate certainty) and misoprostol plus oxytocin (RR 0.70, 95% CI 0.58 to 0.86, low certainty) may reduce PPH ≥ 500 mL compared with oxytocin. Low-certainty evidence suggests that misoprostol, injectable prostaglandins, and ergometrine may make little or no difference to this outcome compared with oxytocin.All agents except ergometrine and injectable prostaglandins were effective for preventing PPH ≥ 1000 mL when compared with placebo or no treatment. High-certainty evidence suggests that ergometrine plus oxytocin (RR 0.83, 95% CI 0.66 to 1.03) and misoprostol plus oxytocin (RR 0.88, 95% CI 0.70 to 1.11) make little or no difference in the outcome of PPH ≥ 1000 mL compared with oxytocin. Low-certainty evidence suggests that ergometrine may make little or no difference to this outcome compared with oxytocin meanwhile the evidence on carbetocin was of very low certainty. High-certainty evidence suggests that misoprostol is less effective in preventing PPH ≥ 1000 mL when compared with oxytocin (RR 1.19, 95% CI 1.01 to 1.42). Despite the comparable relative treatment effects between all uterotonics (except misoprostol) and oxytocin, ergometrine plus oxytocin, misoprostol plus oxytocin combinations and carbetocin were the highest ranked agents for PPH ≥ 1000 mL.Misoprostol plus oxytocin reduces the use of additional uterotonics (RR 0.56, 95% CI 0.42 to 0.73, high certainty) and probably also reduces the risk of blood transfusion (RR 0.51, 95% CI 0.37 to 0.70, moderate certainty) when compared with oxytocin. Carbetocin, injectable prostaglandins and ergometrine plus oxytocin may also reduce the use of additional uterotonics but the certainty of the evidence is low. No meaningful differences could be detected between all agents for maternal deaths or severe morbidity as these outcomes were rare in the included randomised trials where they were reported.The two combination regimens were associated with important side effects. When compared with oxytocin, misoprostol plus oxytocin combination increases the likelihood of vomiting (RR 2.11, 95% CI 1.39 to 3.18, high certainty) and fever (RR 3.14, 95% CI 2.20 to 4.49, moderate certainty). Ergometrine plus oxytocin increases the likelihood of vomiting (RR 2.93, 95% CI 2.08 to 4.13, moderate certainty) and may make little or no difference to the risk of hypertension, however absolute effects varied considerably and the certainty of the evidence was low for this outcome.Subgroup analyses did not reveal important subgroup differences by mode of birth (caesarean versus vaginal birth), setting (hospital versus community), risk of PPH (high versus low risk for PPH), dose of misoprostol (≥ 600 mcg versus < 600 mcg) and regimen of oxytocin (bolus versus bolus plus infusion versus infusion only).

AUTHORS' CONCLUSIONS

All agents were generally effective for preventing PPH when compared with placebo or no treatment. Ergometrine plus oxytocin combination, carbetocin, and misoprostol plus oxytocin combination may have some additional desirable effects compared with the current standard oxytocin. The two combination regimens, however, are associated with significant side effects. Carbetocin may be more effective than oxytocin for some outcomes without an increase in side effects.

The effect of initiating intravenous oxytocin infusion before uterine incision on the blood loss during elective cesarean section: a randomized clinical trial

Objective: This study compares the effect of starting intravenous oxytocin infusion early before uterine incision versus late after umbilical cord clamping on the blood loss during elective cesarean section (CS). Methods: A single-blinded randomized clinical trial conducted on 200 pregnant women at term (>37 weeks) gestation scheduled for elective CS were assigned to either IV infusion of 30 IU of oxytocin started before uterine incision (Group I) or started immediately after clamping the umbilical cord (Group II). The primary outcome was the mean volume of blood loss during CS. The secondary outcomes included the mean volume of postoperative blood loss, the mean reduction in the hemoglobin and hematocrit levels, the need for additional uterotonics, blood transfusion and additional surgical procedures. Results: The baseline characteristics of both groups are quiet similar. No statistical significant difference between both groups as regard to pre- and postpartum hemoglobin levels (p = .06 and 0.24 respectively) and hematocrit values (p = .12 and .51 respectively). There was a significant reduction in the intraoperative blood loss in group I compared with group II (432.7 ± 90.6 versus 588.9 ± 96.3 mL respectively, p = .001). The need for additional uterotonics was more frequent in the group II (19 women) than in group I (seven women) with statistical significance (p = .002). No differences between both groups regarding the need for blood transfusion or additional surgical procedures. Conclusions: Initiating intravenous oxytocin infusion before uterine incision during elective CS could be associated with reduction in the intraoperative blood loss and the need for additional uterotonics.

Uterotonic agents for preventing postpartum haemorrhage: a network meta-analysis

BACKGROUND

Postpartum haemorrhage (PPH) is the leading cause of maternal mortality worldwide. Prophylactic uterotonic drugs can prevent PPH, and are routinely recommended. There are several uterotonic drugs for preventing PPH but it is still debatable which drug is best.

OBJECTIVES

To identify the most effective uterotonic drug(s) to prevent PPH, and generate a ranking according to their effectiveness and side-effect profile.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (1 June 2015), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) for unpublished trial reports (30 June 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised controlled comparisons or cluster trials of effectiveness or side-effects of uterotonic drugs for preventing PPH.Quasi-randomised trials and cross-over trials are not eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

At least three review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We estimated the relative effects and rankings for preventing PPH ≥ 500 mL and PPH ≥ 1000 mL as primary outcomes. We performed pairwise meta-analyses and network meta-analysis to determine the relative effects and rankings of all available drugs. We stratified our primary outcomes according to mode of birth, prior risk of PPH, healthcare setting, dosage, regimen and route of drug administration, to detect subgroup effects.The absolute risks in the oxytocin are based on meta-analyses of proportions from the studies included in this review and the risks in the intervention groups were based on the assumed risk in the oxytocin group and the relative effects of the interventions.

MAIN RESULTS

This network meta-analysis included 140 randomised trials with data from 88,947 women. There are two large ongoing studies. The trials were mostly carried out in hospital settings and recruited women who were predominantly more than 37 weeks of gestation having a vaginal birth. The majority of trials were assessed to have uncertain risk of bias due to poor reporting of study design. This primarily impacted on our confidence in comparisons involving carbetocin trials more than other uterotonics.The three most effective drugs for prevention of PPH ≥ 500 mL were ergometrine plus oxytocin combination, carbetocin, and misoprostol plus oxytocin combination. These three options were more effective at preventing PPH ≥ 500 mL compared with oxytocin, the drug currently recommended by the WHO (ergometrine plus oxytocin risk ratio (RR) 0.69 (95% confidence interval (CI) 0.57 to 0.83), moderate-quality evidence; carbetocin RR 0.72 (95% CI 0.52 to 1.00), very low-quality evidence; misoprostol plus oxytocin RR 0.73 (95% CI 0.60 to 0.90), moderate-quality evidence). Based on these results, about 10.5% women given oxytocin would experience a PPH of ≥ 500 mL compared with 7.2% given ergometrine plus oxytocin combination, 7.6% given carbetocin, and 7.7% given misoprostol plus oxytocin. Oxytocin was ranked fourth with close to 0% cumulative probability of being ranked in the top three for PPH ≥ 500 mL.The outcomes and rankings for the outcome of PPH ≥ 1000 mL were similar to those of PPH ≥ 500 mL. with the evidence for ergometrine plus oxytocin combination being more effective than oxytocin (RR 0.77 (95% CI 0.61 to 0.95), high-quality evidence) being more certain than that for carbetocin (RR 0.70 (95% CI 0.38 to 1.28), low-quality evidence), or misoprostol plus oxytocin combination (RR 0.90 (95% CI 0.72 to 1.14), moderate-quality evidence)There were no meaningful differences between all drugs for maternal deaths or severe morbidity as these outcomes were so rare in the included randomised trials.Two combination regimens had the poorest rankings for side-effects. Specifically, the ergometrine plus oxytocin combination had the higher risk for vomiting (RR 3.10 (95% CI 2.11 to 4.56), high-quality evidence; 1.9% versus 0.6%) and hypertension [RR 1.77 (95% CI 0.55 to 5.66), low-quality evidence; 1.2% versus 0.7%), while the misoprostol plus oxytocin combination had the higher risk for fever (RR 3.18 (95% CI 2.22 to 4.55), moderate-quality evidence; 11.4% versus 3.6%) when compared with oxytocin. Carbetocin had similar risk for side-effects compared with oxytocin although the quality evidence was very low for vomiting and for fever, and was low for hypertension.

AUTHORS' CONCLUSIONS

Ergometrine plus oxytocin combination, carbetocin, and misoprostol plus oxytocin combination were more effective for preventing PPH ≥ 500 mL than the current standard oxytocin. Ergometrine plus oxytocin combination was more effective for preventing PPH ≥ 1000 mL than oxytocin. Misoprostol plus oxytocin combination evidence is less consistent and may relate to different routes and doses of misoprostol used in the studies. Carbetocin had the most favourable side-effect profile amongst the top three options; however, most carbetocin trials were small and at high risk of bias.Amongst the 11 ongoing studies listed in this review there are two key studies that will inform a future update of this review. The first is a WHO-led multi-centre study comparing the effectiveness of a room temperature stable carbetocin versus oxytocin (administered intramuscularly) for preventing PPH in women having a vaginal birth. The trial includes around 30,000 women from 10 countries. The other is a UK-based trial recruiting more than 6000 women to a three-arm trial comparing carbetocin, oxytocin and ergometrine plus oxytocin combination. Both trials are expected to report in 2018.Consultation with our consumer group demonstrated the need for more research into PPH outcomes identified as priorities for women and their families, such as women's views regarding the drugs used, clinical signs of excessive blood loss, neonatal unit admissions and breastfeeding at discharge. To date, trials have rarely investigated these outcomes. Consumers also considered the side-effects of uterotonic drugs to be important but these were often not reported. A forthcoming set of core outcomes relating to PPH will identify outcomes to prioritise in trial reporting and will inform futures updates of this review. We urge all trialists to consider measuring these outcomes for each drug in all future randomised trials. Lastly, future evidence synthesis research could compare the effects of different dosages and routes of administration for the most effective drugs.

Cost effectiveness analysis of carbetocin during cesarean section in a high volume maternity unit

AIM

To evaluate the cost effectiveness of carbetocin compared to oxytocin when used as prophylaxis against post-partum hemorrhage (PPH) during cesarean deliveries.

METHODS

A systematic review of the literature was performed to identify randomized controlled trials that compared the use of carbetocin to oxytocin in the context of cesarean deliveries. Cost effectiveness analysis was then performed using secondary data from the perspective of a maternity unit within the Malaysian Ministry of Health, over a 24 h time period.

RESULTS

Seven randomized controlled trials with over 2000 patients comparing carbetocin with oxytocin during cesarean section were identified. The use of carbetocin in our center, which has an average of 3000 cesarean deliveries annually, would have prevented 108 episodes of PPH, 104 episodes of transfusion and reduced the need for additional uterotonics in 455 patients. The incremental cost effectiveness ratio of carbetocin for averting an episode of PPH was US$278.70.

CONCLUSION

Reduction in retreatment, staffing requirements, transfusion and potential medication errors mitigates the higher index cost of carbetocin. From a pharmacoeconomic perspective, in the context of cesarean section, carbetocin was cost effective as prophylaxis against PPH. Ultimately, the relative value placed on the outcomes above and the individual unit's resources would influence the choice of uterotonic.

Lack of controlled studies investigating the risk of postpartum haemorrhage in cesarean delivery after prior use of oxytocin: a scoping review

BACKGROUND

Postpartum haemorrhage (PPH) is a major cause of maternal mortality and morbidity worldwide. Experimental and clinical studies indicate that prolonged oxytocin exposure in the first or second stage of labour may be associated with impaired uterine contractility and an increased risk of atonic PPH. Therefore, particularly labouring women requiring cesarean delivery constitute a subset of patients that may exhibit an unpredictable response to oxytocin. We mapped the evidence for comparative studies investigating the hypothesis whether the risk for PPH is increased in women requiring cesarean section after induction or augmentation of labour.

METHODS

We performed a systematic literature search for clinical trials in Medline, Embase, Web of Science, and the Cochrane Library (May 2016). Additionally we searched for ongoing or unpublished trials in clinicaltrials.gov and the WHO registry platform. We identified a total of 36 controlled trials investigating the exogenous use of oxytocin in cesarean section. Data were extracted for study key characteristics and the current literature literature was described narratively.

RESULTS

Our evidence map shows that the majority of studies investigating the outcome PPH focused on prophylactic oxytocin use compared to other uterotonic agents in the third stage of labour. Only 2 dose-response studies investigated the required oxytocin dose to prevent uterine atony after cesarean delivery for labour arrest. These studies support the hypotheses that labouring women exposed to exogenous oxytocin require a higher oxytocin dose after delivery than non-labouring women to prevent uterine atony after cesarean section. However, the study findings are flawed by limitations of the study design as well as the outcome selection. No clinical trial was identified that directly compared exogenous oxytocin versus no oxytocin application before intrapartum cesarean delivery.

CONCLUSION

Despite some evidence from dose-response studies that the use of oxytocin may increase the risk for PPH in intrapartum cesarean delivery, current research has not investigated the prepartal application of oxytocin in well controlled clinical trials. It was striking that most studies on exogenous oxytocin are focused on PPH prophylaxis in the third stage of labour without differing between the indications of cesarean section and hence the prepartal oxytocin status.