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Prevention of postpartum haemorrhage: a distributional approach for analysis.

ABSTRACT: BACKGROUND:There is empirical evidence that measured postpartum blood loss has a lognormal distribution. This feature can be used to analyze events of the type 'blood loss greater than a certain cutoff point' using a lognormal approach, which takes into account all the quantitative observations, as opposed to dichotomizing the variable blood loss volume into two categories. This lognormal approach uses all the information contained in the data and is expected to provide more efficient estimates of proportions and relative risk when comparing treatments to prevent postpartum haemorrhage. As a consequence, sample size can be reduced in clinical trials, while keeping the statistical precision requirements. METHODS:The authors illustrate how a lognormal approach can be used in this situation, using data from a clinical trial and the event 'blood loss greater than 1000 mL'. RESULTS:Estimates of the proportions of this event for each treatment, and relative risks obtained with this method are presented and compared with the standard estimates obtained by dichotomizing measured blood loss volume. An example of how the blood loss distributions of two treatments can be compared is also presented. Different scenarios of the sample size needed to compare two treatments or interventions are presented to illustrate how with the lognormal approach the size of a clinical trial can be reduced. CONCLUSIONS:A distributional approach for postpartum blood loss using the lognormal distribution fitted to the data results in more precise estimates of risks of events and relative risks, compared to the use of binomial proportions of events. It also results in reduced required sample size for clinical trials. TRIAL REGISTRATION:This paper reports a secondary analysis for a trial that was registered at clinicaltrials.gov ( NCT00781066 ).

SUBMITTER: Piaggio G

PROVIDER: S-EPMC6020008 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Prevention of postpartum haemorrhage: a distributional approach for analysis.

Piaggio Gilda G Carvalho José Ferreira de JF Althabe Fernando F

Reproductive health 20180622 Suppl 1

<h4>Background</h4>There is empirical evidence that measured postpartum blood loss has a lognormal distribution. This feature can be used to analyze events of the type 'blood loss greater than a certain cutoff point' using a lognormal approach, which takes into account all the quantitative observations, as opposed to dichotomizing the variable blood loss volume into two categories. This lognormal approach uses all the information contained in the data and is expected to provide more efficient es ...[more]

PMID: 29945633

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Project description:Postpartum haemorrhage (PPH) is the leading cause of maternal mortality in low-income countries and is a significant contributor to severe maternal morbidity and long-term disability. Carbetocin may be an underused uterotonic for prevention of PPH. A number of studies are being conducted that may challenge the place of oxytocin as the first choice of uterotonics for prevention of PPH. This paper describes the current research into carbetocin and ranking of effectiveness of uterotonics that may provide important new information to assist healthcare decision makers to ensure that women receive an effective uterotonic for prevention of PPH.We searched the WHO International Clinical Trials Registry Platform for current studies on effectiveness of carbetocin for prevention of PPH following vaginal delivery with sample sizes large enough to provide quality evidence to support potential changes to international guidelines. We also searched the Cochrane Library for current systematic reviews including carbetocin used in prevention of PPH.Susceptibility to degradation from exposure to heat is one of the key causes of reduced effectiveness of oxytocin in preventing PPH from uterine atony. Although heat stable and effective in preventing PPH, misoprostol is also subject to degradation due to exposure to moisture and produces some side-effects. Other uterotonics (including ergometrine and combinations of oxytocin, ergometrine and misoprostol) are also available and used with varying safety and effectiveness profiles and quality issues. Efforts to reduce maternal mortality from PPH include research studies seeking to identify safe, stable, effective uterotonics. Heat stable carbetocin is the subject of two major clinical studies into its effectiveness in preventing PPH following vaginal deliveries, information that could expand its application for prevention of PPH.Heat stable carbetocin is being investigated as a potential alternative to oxytocin. This paper describes two current clinical trials on carbetocin and a network meta-analysis ranking of all uterotonic agents, including carbetocin, which combined may provide evidence supporting expansion of the use of the heat stable formulation of carbetocin in PPH prevention.

Project description:BackgroundPostpartum haemorrhage (PPH) is a leading cause of preventable maternal mortality worldwide. The World Health Organization (WHO) recommends uterotonic administration for every woman after birth to prevent PPH. There are no standardised data collected in large-scale measurement platforms. The Every Newborn Birth Indicators Research Tracking in Hospitals (EN-BIRTH) is an observational study to assess the validity of measurement of maternal and newborn indicators, and this paper reports findings regarding measurement of coverage and quality for uterotonics.MethodsThe EN-BIRTH study took place in five hospitals in Bangladesh, Nepal and Tanzania, from July 2017 to July 2018. Clinical observers collected tablet-based, time-stamped data. We compared observation data for uterotonics to routine hospital register-records and women's report at exit-interview survey. We analysed the coverage and quality gap for timing and dose of administration. The register design was evaluated against gap analyses and qualitative interview data assessing the barriers and enablers to data recording and use.ResultsObserved uterotonic coverage was high in all five hospitals (> 99%, 95% CI 98.7-99.8%). Survey-report underestimated coverage (79.5 to 91.7%). "Don't know" replies varied (2.1 to 14.4%) and were higher after caesarean (3.7 to 59.3%). Overall, there was low accuracy in survey data for details of uterotonic administration (type and timing). Register-recorded coverage varied in four hospitals capturing uterotonics in a specific column (21.6, 64.5, 97.6, 99.4%). The average coverage measurement gap was 18.1% for register-recorded and 6.0% for survey-reported coverage. Uterotonics were given to 15.9% of women within the "right time" (1 min) and 69.8% within 3 min. Women's report of knowing the purpose of uterotonics after birth ranged from 0.4 to 64.9% between hospitals. Enabling register design and adequate staffing were reported to improve routine recording.ConclusionsRoutine registers have potential to track uterotonic coverage - register data were highly accurate in two EN-BIRTH hospitals, compared to consistently underestimated coverage by survey-report. Although uterotonic coverage was high, there were gaps in observed quality for timing and dose. Standardisation of register design and implementation could improve data quality and data flow from registers into health management information reporting systems, and requires further assessment.

Project description: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.

Project description:ObjectiveTo assess whether secondary prevention, which preemptively treats women with above-average postpartum bleeding, is non-inferior to universal prophylaxis.DesignA cluster-randomised non-inferiority community trial.SettingHealth sub-centres and home deliveries in the Bijapur district of Karnataka, India.PopulationWomen with low-risk pregnancies who were eligible for delivery with an Auxiliary Nurse Midwife at home or sub-centre and who consented to be part of the study.MethodsAuxiliary Nurse Midwifes were randomised to secondary prevention using 800 mcg sublingual misoprostol administered to women with postpartum blood loss ≥350 ml or to universal prophylaxis using 600 mcg oral misoprostol administered to all women during the third stage of labour.Main outcome measuresPostpartum haemoglobin ≤7.8 g/dl, mean postpartum blood loss and postpartum haemoglobin, postpartum haemorrhage rate, transfer to higher-level facilities, acceptability and feasibility of the intervention.ResultsMisoprostol was administered to 99.7% of women as primary prevention. In secondary prevention, 92 (4.7%) women had postpartum bleeding ≥350 ml, of which 90 (97.8%) received misoprostol. The proportion of women with postpartum haemoglobin ≤7.8 g/dl was 5.9 and 8.8% in secondary and primary prevention clusters, respectively [difference -2.9%, one-sided 95% confidence interval (CI) <1.3%]. Postpartum transfer and haemorrhage rates were low (<1%) in both groups. Shivering was more common in primary prevention clusters (P = 0.013).ConclusionSecondary prevention of postpartum haemorrhage with misoprostol is non-inferior to universal prophylaxis based on the primary outcome of postpartum haemoglobin. Secondary prevention could be a good alternative to universal prophylaxis as it medicates fewer women and is an acceptable and feasible strategy at the community level.Tweetable abstractSecondary prevention of postpartum haemorrhage with misoprostol is non-inferior to universal prophylaxis.

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Prevention of postpartum haemorrhage: a distributional approach for analysis.

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Prevention of postpartum haemorrhage: a distributional approach for analysis.

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