Oxytocin quality: evidence to support updated global recommendations on oxytocin for postpartum hemorrhage

Heat stable carbetocin or oxytocin for prevention of postpartum hemorrhage among women at risk: A secondary analysis of the CHAMPION trial

OBJECTIVE

To examine whether the observed non-inferiority of heat-stable carbetocin (HSC), compared with oxytocin, was influenced by biologic (macrosomia, parity 3 or more, or history of postpartum hemorrhage [PPH]) and/or pharmacologic (induction or augmentation) risk factors for PPH.

METHODS

The present study is a secondary analysis of the CHAMPION non-inferiority randomized trial-a two-arm, double-blind, active-controlled study conducted at 23 hospitals in 10 countries, between July 2015 and January 2018. Women with singleton pregnancies, expected to deliver vaginally with cervical dilatation up to 6 cm were eligible. Randomization was stratified by country, with 1:1 assignment. Women in the intervention and control groups received a single intramuscular injection of 100 μg of HSC or 10 IU of oxytocin, respectively. The drugs were administered immediately after birth, and the third stage of labor was managed according to the WHO guidelines. Blood was collected using a plastic drape. For this analysis, we defined a woman as being at risk if she had any one or more of the biologic or pharmacologic risk factor(s).

RESULTS

The HSC and oxytocin arms contained 14 770 and 14 768 women, respectively. The risk ratios (RR) for PPH were 1.29 (95% confidence interval [CI] 1.08-1.53) or 1.73 (95% CI 1.51-1.98) for those with only biologic (macrosomia, parity 3 or more, and PPH in the previous pregnancy) or only pharmacologic (induced or augmented) risk factors, respectively, compared with those with neither risk factors.

CONCLUSIONS

Findings reinforce previous evidence that macrosomia, high parity, history of PPH, and induction/augmentation are risk factors for PPH. We did not find a difference in effects between HSC and oxytocin for PPH among women who were neither induced nor augmented or among those who were induced or augmented.

What do healthcare providers think of the quality of uterotonics? A mixed-methods systematic review

OBJECTIVES

To synthesise evidence on the perceptions of healthcare providers (HCPs) about the quality of oxytocin and misoprostol available in their settings, and their actions as a result of these perceptions.

DESIGN

Mixed-methods systematic review.

ELIGIBILITY CRITERIA

We included quantitative and qualitative studies reporting HCPs' perceptions about oxytocin or misoprostol quality.

DATA SOURCES

We searched CINAHL, Cochrane Library, Ebscohost, Embase, PubMed, Global Index Medicus, Portal regional BVS, PsycNET, Scopus and Web of Science from inception to 31 March 2022 and grey literature.

RISK OF BIAS

We used the Center for Evidence-Based Management critical appraisal tool for surveys. For qualitative studies, we used the Critical Appraisal Skills Programme tool.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers performed study selection, data extraction and quality assessment. We conducted separate quantitative and qualitative syntheses and integrated the evidence into a narrative synthesis (convergent segregated review design).

RESULTS

We included five (three quantitative and two qualitative) studies, of moderate or high quality, conducted in low-income and middle-income countries (LMICs). In the three quantitative studies (N=7065 participants), 8.2-21.3% of HCPs had experienced problems due to known/suspected low-quality oxytocin and 3.3% due to low-quality misoprostol. In the two qualitative studies, perception of oxytocin quality varied. In quantitative studies, when confronted with suspected/known low-quality oxytocin, 29-78% of HCPs would inform a supervisor, 62% would document this in writing, 45-54% would change to another drug and 5-37% would double the dose of oxytocin. Qualitative evidence suggests that many HCPs do not formally report suspected low-quality oxytocin or misoprostol, and use higher doses or additional uterotonics.

CONCLUSIONS

A proportion of HCPs from LMICs perceive oxytocin to be of low quality. There is very limited evidence on their perceptions about misoprostol. Many HCPs do not report suspected low-quality uterotonics but change to another medicine or double the dose of oxytocin.

PROSPERO REGISTRATION NUMBER

CRD42022323812.

Epidemiology and definition of PPH worldwide

Postpartum/peripartum hemorrhage (PPH) is an obstetric emergency complicating 1-10% of all deliveries and is a leading cause of maternal mortality and morbidity worldwide. However, the incidence of PPH differs widely according to the definition and criteria used, the way of measuring postpartum blood loss, and the population being studied with the highest numbers in developing countries. Despite all the significant progress in healthcare, the incidence of PPH is rising due to an incomplete implementation of guidelines, resulting in treatment delays and suboptimal care. A consensus clinical definition of PPH is needed to enable awareness, early recognition, and initiation of appropriate intensive treatment. Unfortunately, the most used definition of PPH based on blood loss ≥500 ml after delivery suffers from inaccuracies in blood loss quantification and is not clinically relevant in most cases, as the amount of blood loss does not fully reflect the severity of bleeding.

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

Background

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

Methods

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

Results

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

Conclusion

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

Midwives' experiences of reducing maternal morbidity and mortality from postpartum haemorrhage (PPH) in Eastern Nigeria

Background

Postpartum haemorrhage (PPH) is one of the major complications of childbirth which may result in maternal morbidity and mortality, especially in low and middle-income countries like Nigeria. Midwives play a vital role in preventing and managing PPH in Nigerian rural communities. The aim of this study is to understand the experiences of midwives in rural maternity care settings in order to provide appropriate support and improve practice.

Methods

An exploratory, qualitative study of a purposive sample of 15 practicing midwives was carried out using semi-structured interviews from November 2018 to February 2019. Data were transcribed verbatim and analyzed using content analysis.

Results

Four themes were identified: 1. interventions for preventing PPH; 2. approaches to managing PPH; 3. challenges of preventing and managing PPH and 4. ways of supporting midwives to overcome these challenges in rural health care settings. Midwives employed various strategies, such as antenatal education, diagnosis and treatment of anaemia to counteract complications from possible PPH. Understanding PPH as a life-threatening condition enabled the midwives to provide holistic and effective management that sometimes involved a multidisciplinary team approach. Inadequate resources and delay in seeking health care, however, militate against their efforts. The midwives also identified the need for continuing education and training to enhance their standards of care.

Conclusion

These midwives in Nigerian rural health care settings engage in preventive practices and active management of PPH though not without barriers, such as inadequate resources. There is a need for midwives in rural areas to have cultural competence, be provided with adequate resources and participate in ongoing education in order to be more effective.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04804-x.

Preclinical Safety and Pharmacokinetics of Heat Stable Oxytocin in Sublingual Fast-Dissolving Tablet Formulation

The work reported here focuses on an evaluation of a novel heat stable formulation of a uterotonic peptide drug oxytocin involving stability testing under elevated temperatures and toxicokinetic response generated by sublingual (SL) administration in rabbits. The formulation was thermotolerant, maintaining the potency of oxytocin in the form of a fast-dissolving tablet at the end of 2-year storage at 30 °C/65% relative humidity with less than 5% loss in oxytocin content based on analytical high performance liquid chromatography (HPLC). The toxicokinetic results in rabbits showed that the fast-dissolving tablet was safe without any reactogenicity or toxicity associated with SL administration or the excipients present in the formulation. The SL route elicited rapid absorption of oxytocin in plasma within 5 min of administration although lower than intramuscular (IM) administration. IM resulted in area under the curve (AUC) values approximately 5 times higher than SL oxytocin. However, due to the limitations encountered during SL administration in an anesthetized rabbit model, the relevance of heat stable oxytocin formulation that has the flexibility to be adapted in different formats may warrant a human clinical study to determine whether therapeutically relevant plasma levels for treating postpartum hemorrhage can be generated via alternate non-injectable routes of administration.

Mass balance method for SI-traceable purity assignment of synthetic oxytocin

Oxytocin is not only a significant peptide drug for enhancing uterine contractions, but also an emerging biomarker and therapeutic target of mental disorders in clinical practice. There is a pressing need for the standardization of oxytocin assays because of its low pharmaceutical quality and large variations among measurement approaches. International System of Units (SI)-traceable analytical methods and well-characterized pure reference materials are urgently needed to set up standard reference measurement systems in laboratory medicine, ensuring the accuracy and comparability of test results. Herein, the purity assignment of a synthetic oxytocin containing a disulfide linkage was established based on a mass balance method, which had never been performed for a cross-linked peptide. An in-house validated liquid chromatography-high-resolution tandem mass spectrometry method was developed for the determination of structurally-related impurities in the study material. Twenty-one structurally-related impurities including deamidations, oxidations, and amino acid insertions, etc. ranging from 0.05 mg g^-1 to 15.65 mg g^-1 were identified and quantified by applying a hierarchy calibration concept. This study subsequently discusses a fit for purpose assessment for non-peptide related impurities including water, non-volatile counterions, inorganic elements, and volatile organic compounds that were determined using coulometric Karl Fischer titration, ion chromatography, inductively coupled plasma mass spectrometry, and headspace gas chromatography-mass spectrometry, respectively. The resulting assigned value (796.5 mg g^-1) is determined to be traceable to SI associated with a small measurement uncertainty of 6.5 mg g^-1 (k = 2). The method developed in this study has been verified through an international key comparison jointly coordinated by the Bureau International des Poids et Mesures and the National Institute of Metrology.

Postpartum hemorrhage: Could oxytocin be the cause? Results from a morbidity and mortality review to enhance quality, safety, and relevance of care

INTRODUCTION

A sudden postpartum hemorrhage (PPH) increase has been subjectively observed during summer 2018 in our level-3 maternity, despite following all official recommendations for PPH care. This observation led us to conduct a morbi-mortality review to understand morbidity increase reasons.

METHODS

We conducted a first retrospective comparative cohort study from 2017 to 2018 to compare PPH rates. We conducted a second comparative study to determine the factors that may have led to an increase in PPH. One of the initial hypotheses of increased PPH was related to the weakness of oxytocin, exposed to high outside temperatures. The eight-day delivery records were analyzed, as follow: the high-frequency period of PPH (EXPOSED), the batch replacement of oxytocin (NON EXPOSED), and the same period of the previous year (1 YEAR BEFORE). We studied all known PPH risk factors: preconception, pregnancy, childbirth, and human, climatic, or material organizational factors in this maternity.

RESULTS

322 women were included: 111, 92, and 119 in the EXPOSED, NON EXPOSED, and 1 YEAR BEFORE groups, respectively. Sociodemographic data of the 3 groups were not different. The rate of PPH in the EXPOSED was significantly higher than that of NON EXPOSED, and 1 YEAR BEFORE: 20.7 %, 7.6 %, and 5.8 %, respectively (p = 0.0077). In the multivariate analysis, the reduction in PPH (EXPOSED vs NON EXPOSED) after changing the oxytocin batch was significant (OR 0.38 [0.14-0.91], p = 0.039).

CONCLUSION

Changing oxytocin batches during this hot period reduced significantly the PPH rate and maternal morbidity in our experience.