The Effect of Combined Oxytocin-Misoprostol Versus Oxytocin and Misoprostol Alone in Reducing Blood Loss at Cesarean Delivery: A Prospective Randomized Double-Blind Study

WITHDRAWN: The Effect of Preoperative Intravenous Tranexamic Acid Versus Rectal Misoprostol in Reducing Blood Loss During and After Elective Cesarean Delivery in Primigravida: A Double-Blinded, Randomized, Comparative-Placebo Trial

The publisher regrets that this article has been temporarily removed. A replacement will appear as soon as possible in which the reason for the removal of the article will be specified, or the article will be reinstated. The full Elsevier Policy on Article Withdrawal can be found at: https://www.elsevier.com/about/policies/article-withdrawal.

Highly Specific Detection of Oxytocin in Saliva

Oxytocin is a peptide neurophysin hormone made up of nine amino acids and is used in induction of one in four births worldwide (more than 13 percent in the United States). Herein, we have developed an antibody alternative aptamer-based electrochemical assay for real-time and point-of-care detection of oxytocin in non-invasive saliva samples. This assay approach is rapid, highly sensitive, specific, and cost-effective. Our aptamer-based electrochemical assay can detect as little as 1 pg/mL of oxytocin in less than 2 min in commercially available pooled saliva samples. Additionally, we did not observe any false positive or false negative signals. This electrochemical assay has the potential to be utilized as a point-of-care monitor for rapid and real-time oxytocin detection in various biological samples such as saliva, blood, and hair extracts.

Preventing postpartum hemorrhage with combined therapy rather than oxytocin alone

Postpartum hemorrhage is the leading cause of maternal morbidity and mortality worldwide, with uterine atony estimated to account for 70% to 80% of cases, thereby remaining the single most common cause. Pharmacotherapy remains the first-line preventative therapy for postpartum hemorrhage. These therapies may be single (oxytocin, carbetocin, methylergonovine, ergometrine, misoprostol, prostaglandin analogs, or tranexamic acid) or combination therapies, acting in an additive, infra-additive, or synergistic fashion to prevent postpartum hemorrhage. Evidence is strong for the use of oxytocin, the first-line uterotonic agent in the United States for prevention of postpartum hemorrhage. Although carbetocin, a long-acting analog of oxytocin, is not yet available for use in the United States, it is likely the most effective single pharmacologic therapy for prevention of postpartum hemorrhage and need for additional uterotonics. Use of second-line uterotonics such as methylergonovine, misoprostol, and carboprost in combination with oxytocin has an additive or synergistic effect and a greater risk reduction for postpartum hemorrhage prevention compared with oxytocin alone. Therefore, combined therapy rather than oxytocin alone should be advised for preventing postpartum hemorrhage. Tranexamic acid has been found to be both effective and safe for decreasing maternal mortality in women with postpartum hemorrhage, and prophylactic use of tranexamic acid may decrease the need for packed red blood cell transfusions and/or uterotonics. The WOMAN-2 Trial, designed to assess if tranexamic acid prevents postpartum hemorrhage in women with moderate to severe anemia undergoing vaginal delivery, is currently recruiting participants. The additive, infra-additive, or synergistic action of oxytocin in combination with other second-line therapies deserves further study.

The efficacy of misoprostol in reducing intraoperative blood loss in women undergoing elective cesarean section. A systematic review and meta-analysis

OBJECTIVES

To evaluate the efficacy of misoprostol to minimized blood loss during and after cesarean delivery (CD).

SEARCH STRATEGY

Screening of MEDLINE, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials from inception to February 2021 using the keywords related to misoprostol, CD, postpartum hemorrhage, and intraoperative blood loss and their MeSH terms.

SELECTION CRITERIA

Only RCTs were included. Participants included women undergoing CD whether elective or selective. Thirty studies including 6593 women, 26 in English, 2 in Thai, 1 in French, and 1 in Chinese.

DATA COLLECTION AND ANALYSIS

Data from all selected studies were extracted independently by two authors. Data extracted included location of the trial, sample size, inclusion and exclusion criteria, participants characteristics, intervention details including timing, dose, and route of drug administration. Outcomes assessed included estimated intraoperative and postoperative blood loss, occurrence of postpartum hemorrhage, the need for additional uterotonics, and hemoglobin difference.

MAIN RESULTS

Four studies (968 women) compared preoperative to postoperative misoprostol and found a mean difference in intraoperative blood loss of -205.00 (-339.22, -70.77), p = 0.003 and in postoperative blood loss -216.27 (-347.08, -85.46), p < 0.001 and a significantly lower need for additional uterotonics with a risk ratio of 0.54 (0.46, 0.64), p < 0.00001. Twenty-two studies (4701 participants) compared misoprostol to oxytocin. There was a mean difference in intraoperative blood loss of -108.43 (-156.04, -60.82), p < 0.0001. Nine of these trials with 1978 participants evaluated postoperative blood loss. These found a mean difference of -64.12 (-116.19, -12.04) with a p = 0.02. Fourteen trials with 3166 participants measured the difference between preoperative and postoperative hemoglobin. These found a mean difference of -0.25 (-0.35, -0.15) with a p < 0.001. Twenty trials with 4416 participants measured the need for administration of additional uterotonics. These found a risk ratio of 0.62 (0.49, 0.78) with a p value of <0.001.

CONCLUSION

The combined use of misoprostol and oxytocin during CD is effective in reducing blood loss during and after CD.

Side-effects of oxytocin in postpartum hemorrhage: a systematic review and meta-analysis

OBJECTIVE

To evaluate the side-effects of oxytocin for the prevention of postpartum hemorrhage (PPH) in randomized controlled trials (RCTs).

METHODS

Electronic databases (Web of Science, Embase, PubMed, Elsevier ScienceDirect, the Cochrane Library, and ClinicalTrials.gov) were searched from the beginning of indexing to Sep 2021. RCTs comparing oxytocin with non-oxytocin uterotonic agent(s) or non-pharmacologic interventions for the prevention of PPH were eligible.

RESULTS

Overall, sixty-one RCTs meeting the inclusion criteria were included, involving 68834 participants. Twenty-seven types of side-effects were reported in this study. There were 24, 35, or 2 trials assessed as high medium and low quality, respectively. Compared with non-oxytocin, oxytocin had significantly lower risk for shivering (RR=0.31, 95% CI=0.23-0.41, n=36680), fever (RR=0.27, 95% CI=0.20-0.37, n=34031), and diarrhea (RR=0.48, 95% CI=0.35-0.66, n=30883). Other side-effects were not found associated with oxytocin.

CONCLUSION

Oxytocin use was association with a significantly lower incidence of shivering, fever, and diarrhea events and did not increase risk of other side-effects during the third stage of labor. These observations may aid obstetricians and gynecologists in weighing up the benefits and risks associated with oxytocin in prevention and treatment of PPH during the third stage of labor.

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.

Rectal vs. sublingual misoprostol in cesarean section: Three‑arm, randomized clinical trial

BACKGROUND

Misoprostol is a myometrial stimulant with uterotonic properties and can be administered rectally, vaginally, or sublingually. Numerous studies have investigated the effect of misoprostol on the prevention and treatment of PPH (postpartum hemorrhage) after vaginal delivery, but its use to control PPH during cesarean section has not been widely studied.

METHODS

In this clinical trial study, 180 pregnant women who were candidates for cesarean section were included in the study. They were divided into 3 groups of 60 people (sublingual misoprostol group, rectal misoprostol group, control group). In all three groups, the volume of blood lost was recorded in the checklist at the end of surgery. Data were entered into SPSS software and analyzed.

RESULTS

The mean bleeding in the control group was 225.4±63.9, while it was 137.9±33.8 and 118.9±28.5 in the sublingual misoprostol group and rectal misoprostol group, respectively. We had significantly more bleeding in the control group (p<0.001) compared to the other two groups.

CONCLUSION

These results confirm the positive effect of misoprostol in reducing bleeding and show the superiority of using rectal misoprostol compared to other methods of reducing bleeding during cesarean section.

Comparing and combining evidence of treatment effects in randomized and nonrandomized studies on the use of misoprostol to prevent postpartum hemorrhage

OBJECTIVE

Postpartum hemorrhage (PPH) is a preventable condition and the main cause of maternal death worldwide. Evidence on the effectiveness of misoprostol in the prevention of PPH has been generated from both randomized controlled trials (RCTs) and nonrandomized studies (NRS). This study aimed to compare the results of RCTs and NRS, and to compare Classical and Bayesian approaches of combining the results of RCTs and NRS on the use of misoprostol versus placebo in the prevention of PPH.

METHODS

We searched MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials for appropriate studies. We pooled estimates of effects from RCTs and NRS seperately, using random-effects models, then merged them using classical and Bayesian random effects meta-analysis.

RESULTS

A total of 34 studies (20 RCTs and 14 NRS) involving 74 204 participants were identified. The summary odds ratio (OR) from RCTs for the use of misoprostol in the prevention of PPH was 0.69 (95% confidence interval [CI]: 0.59 to 0.80). The summary OR from NRS was 0.46 (95% CI: 0.36 to 0.63). Classical and Bayesian approaches of combining the two study designs both showed benefit of misoprostol in preventing PPH, with similar effects.

CONCLUSIONS

Both RCTs and NRS show comparable significant benefit for the use of misoprostol in the prevention of PPH.

Misoprostol as an adjunct to oxytocin can reduce postpartum-haemorrhage: a propensity score-matched retrospective chart review in Bamenda-Cameroon, 2015-2016

BACKGROUND

There is some evidence that suggests misoprostol may supplement the action of oxytocin in preventing post-partum haemorrhage (PPH). The primary objective of this study was to determine the effect of the administration of 600 μg misoprostol in addition to oxytocin versus oxytocin alone, on the risk of PPH among pregnant women after delivery. The secondary objectives were to determine the effects of the above combination on maternal death and blood transfusion among pregnant women after delivery; and to determine the incidence of PPH, its case fatality, and the maternal mortality ratio in our hospital.

METHODS

Design and setting: Retrospective chart review of 1736 women delivering at the Regional Hospital Bamenda Cameroon, between 2015 and 2016. This was a pre versus post study following a policy change in the prevention of PPH. Exposure groups: One group received oxytocin-misoprostol (January-April 2016: period after policy change), and the second group received oxytocin-only (January-April 2015: period before policy change) after delivery.

OUTCOMES

The primary outcome was PPH, and the secondary outcomes were maternal death and blood transfusion.

STATISTICAL ANALYSIS

A 1:1 matching with replacement was done with the propensity score (PS). The groups were compared using PS matching with conditional logistic regression on the matched pairs as the main analysis. A sensitivity analysis was done using other PS adjustment methods and multiple regression.

RESULTS

Of the 1736 women included in this study, 1238 were matched and compared. Women who received oxytocin-misoprostol were less likely to have PPH as compared to those receiving oxytocin-only (odds ratio [OR] 0.22, 95% confidence interval [CI] 0.08, 0.59, p = 0.003). This reduced odds of PPH was upheld in the different sensitivity analyses. There were no significant differences in the odds of maternal death and the use of blood transfusions between the two groups: OR 3.91, 95% CI [0.44, 35.08], p = 0.22, and OR 0.89, 95% CI [0.14-5.63], p = 0.91, respectively. Sensitivity analyses showed similar results. The incidence of PPH was 2.9% (before adding misoprostol the incidence was 4.4% and after adding misoprostol it was 1.5%), the case fatality rate of PPH was 1.96%, and the overall maternal mortality ratio in the hospital was 293 maternal deaths/100000 life births.

CONCLUSION

Our evidence suggests that using 600 μg misoprostol as an add-on to oxytocin in the prevention of post-partum haemorrhage significantly reduces the odds of PPH without affecting other maternal outcomes.

Comparison of the Effect of Intravenous Tranexamic Acid and Sublingual Misoprostol on Reducing Bleeding After Cesarean Section: A Double-Blind Randomized Clinical Trial

Purpose

To evaluate the effects of intravenous tranexamic acid (TA) and sublingual misoprostol on reducing bleeding after cesarean section.

Materials

One hundred and fifty-eight participants with term pregnancies scheduled for cesarean section were randomly divided into two groups. In M group, two sublingual misoprostol pills (400 mg) were administrated, immediately after the delivery. In TA group, ten minutes before skin incision, TA ampoule (1 g) was injected. In both groups, immediately after the delivery, 20 units of oxytocin in 1 L ringer lactate with speed of 1000 CC/h was injected. At the end of the operation, the amount of bleeding was measured based on the number of small and large gauzes, the blood in the suction container and the difference of patient's hemoglobin before and 24 h after surgery.

Results

Hemoglobin level reduction in the TA group was higher than the M group (- 2.45 ± 0.84 vs - 2.14 ± 1.38 g/dL) (P < 0.001). Furthermore, number of used gauze and blood suction in the TA group was significantly higher compared to sublingual misoprostol (4.67 ± 1.34 vs 3.25 ± 1.31 and 260.25 ± 79.06 vs 193.94 ± 104.79 cc, respectively) (P < 0.001). Mean blood pressure during the entire duration of surgery in the TA group decreased significantly as compared to the M group (P < 0.001).

Conclusion

Total bleeding was significantly lower in sublingual misoprostol as compared to the tranexamic acid group. Furthermore, in misoprostol group hemodynamic variables were stabilized greater than tranexamic acid group.

Registration Number

IRCT201708308611N6.

Effect of Melatonin on Blood Loss After Cesarean Section: A Prospective Randomized Double-Blind Trial

Background and Objectives

The similarities between the melatonin and oxytocin signaling could lead to increased contractility of myometrium. We designed this randomized double-blind, placebo-controlled trial to evaluate the efficacy of melatonin in reduction of blood loss during and after the lower segment cesarean section.

Methods

One hundred and twenty patients who had been scheduled for cesarean section under spinal anesthesia were enrolled in the study. We randomly allocated them to one of the three following groups to receive either melatonin 3 mg (M₃), melatonin 6 mg (M₆), or placebo (P) sublingually 20 min before the surgery. The hemoglobin levels before and 12 h after surgery, the mean weight of the materials used in the operation time, the need for additional oxytocic therapy, and the incidence of adverse effects were probed and recorded.

Results

There was a significant difference between the group M₆ and both M₃ and P in the mean weight of the materials (p = .024 and .041, respectively) and between M₆ and P groups in terms of mean decrease in hemoglobin during 12 h after cesarean section (p = .029).

Conclusion

Using 6 mg melatonin, sublingually, as a premedication in patients undergoing cesarean section with spinal anesthesia could statistically reduce the amount of blood loss after the lower segment cesarean section, although it may not be clinically meaningful.Registration number: ACTRN12612000117819 and ClinicalTrials.gov Identifier: NCT01572805.

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.

Comparison of rectal misoprostol's effect when used before and after a cesarean section on post-cesarean bleeding

OBJECTIVE

Cesarean section is a common surgery in women. Different drugs are used to control its bleeding. This study compared the effect of using rectal misoprostol before and after surgery on the amount of post-cesarean bleeding.

MATERIALS AND METHODS

A number of 120 women who were admitted to our hospital because of elective cesarean section entered this clinical trial. They were divided into two groups. The first (before surgery) group received 400μg of rectal misoprostol before the cesarean section and the second (after surgery) group after the surgery. The amount of bleeding was measured in both groups. The data were recorded and analyzed.

RESULTS

Their mean of age was 29.1±6.1 years old. The mean of blood loss volume was 283±147mL in the before-surgery group and 294±108mL in the after-surgery group (P=0.6). There was no significant difference in the level of post-operation hemoglobin between the two groups. However, the frequency of need for additional uterotonics was 47% in the first group and 85% in the second group (P<0.001).

CONCLUSION

There seems to be no significant difference in administering rectal misoprostol before or after the surgery, but the need for additional uterotonics is reduced if it is used before the surgery.

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.