Calibrated delivery drape versus indirect gravimetric technique for the measurement of blood loss after delivery: a randomized trial

Early feasibility and usability study of a novel obstetric blood loss quantifying device

OBJECTIVE

To study the accuracy and usability of a novel obstetric blood loss quantifying tool in clinical settings.

METHODS

A mixed-methods study was conducted in an Irish tertiary maternity unit. The accuracy of measuring the blood content (hemoglobin concentration) of elective Caesarean section birth waste with a novel obstetric blood loss quantifying device was compared, using Bland-Altman and correlation analysis, with staff volumetry and a reference hemoglobinometer. Hospital staff (nurses, midwives and doctors) opinion of the usability of the device was studied by an anonymous questionnaire which generated a System Usability Scale (SUS) score. SUS scores range from 0 to 100 with higher scores reflecting greater usability.

RESULTS

The device was used by 19 different hospital staff members (nine nurses, four midwives and six doctors) in 19 elective Caesarean deliveries that had varying levels of PPH risk. Bland-Altman analysis produced mean biases of -0.7 ± 1.5 g/dL and 0.2 ± 1.2 g/dL for the device and staff measurements respectively. The width of the limits of agreement was narrower for device measurements than for staff measurements (4.5 g/dL and 5.7 g/dL respectively). The device's measurements of hemoglobin content correlated more strongly with the hemoglobinometer rather than with hospital staff measurements (Spearman correlation coefficients of 0.9 and 0.6 respectively). This suggests that the device is more accurate in determining the blood content of the birth waste than hospital staff volumetric measurements. Hospital staff members assigned the device a mean SUS score of 82 which suggests that the device is highly usable.

CONCLUSION

An early feasibility study in clinical settings suggests that a novel device for quantifying obstetric blood loss was more accurate than volumetry in measuring the hemoglobin content of birth waste. Health professionals also found the device highly usable. This data suggests that there is much potential in transitioning from a "human-made" to a "machine-made" assessment of blood loss. Future studies will entail additional testing of the device to assess its impact on the morbidities associated with postpartum hemorrhage.

Two Postpartum Blood Collection Devices: The Brass-V Drape and MaternaWell Tray-As Experienced by Birth Attendants and Birthing Women-A Questionnaire-Based Randomised Study

Background

Postpartum haemorrhage is the leading cause of preventable maternal mortality worldwide. Early identification and prompt management of postpartum haemorrhage improve outcomes. Objective assessment of postpartum blood loss is an important step in identifying postpartum haemorrhage. The Brass-V drape and MaternaWell tray have been designed for routine measurement of postpartum blood loss. The perceived utility and acceptability of these devices to the parturients and birth attendants still begged exploring.

Objective

To assess the perceived usefulness and ease of use of a Brass-V drape versus a MaternaWell tray for the collection of postpartum blood loss.

Methods

We conducted a prospective parallel randomised trial, employing a questionnaire to assess the experiences of birth attendants and birthing women who used these devices. The study was conducted at site B midwife obstetric unit in Khayelitsha Cape Town. Pregnant women presenting in early labour were approached for voluntary participation. After informed consent was obtained, participants were randomly assigned to the Brass-V drape or the MaternaWell tray, which the birth attendant placed after the birth of the baby.

Results

There were 63 participants, of which 33 were assigned to the MaternaWell tray and 30 to the Brass-V drape. Birth attendants indicated a desire to use the MaternaWell tray (30 (90%)) or Brass-V drape (26 (87%)) in future deliveries. The parturients were also in favour of the future use of MaternaWell tray (33 (100%)) and Brass-V drape (28 (93%)). Ease of measurement favoured the Brass V-drape, and ease of placement favoured the MaternaWell tray. Five (8%) participants experienced postpartum haemorrhage, two with the MaternaWell tray and three with the Brass-V drape. One parturient required hospital transfer.

Conclusion

The responses of the birth attendants and parturients were positive. The MaternaWell tray has the benefit of reuse and lower cost and is an acceptable alternative to the Brass-V drape. Both devices aid in the early recognition of postpartum haemorrhage.

Strategies for optimising early detection and obstetric first response management of postpartum haemorrhage at caesarean birth: a modified Delphi-based international expert consensus

OBJECTIVE

There are no globally agreed on strategies on early detection and first response management of postpartum haemorrhage (PPH) during and after caesarean birth. Our study aimed to develop an international expert's consensus on evidence-based approaches for early detection and obstetric first response management of PPH intraoperatively and postoperatively in caesarean birth.

DESIGN

Systematic review and three-stage modified Delphi expert consensus.

SETTING

International.

POPULATION

Panel of 22 global experts in PPH with diverse backgrounds, and gender, professional and geographic balance.

OUTCOME MEASURES

Agreement or disagreement on strategies for early detection and first response management of PPH at caesarean birth.

RESULTS

Experts agreed that the same PPH definition should apply to both vaginal and caesarean birth. For the intraoperative phase, the experts agreed that early detection should be accomplished via quantitative blood loss measurement, complemented by monitoring the woman's haemodynamic status; and that first response should be triggered once the woman loses at least 500 mL of blood with continued bleeding or when she exhibits clinical signs of haemodynamic instability, whichever occurs first. For the first response, experts agreed on immediate administration of uterotonics and tranexamic acid, examination to determine aetiology and rapid initiation of cause-specific responses. In the postoperative phase, the experts agreed that caesarean birth-related PPH should be detected primarily via frequently monitoring the woman's haemodynamic status and clinical signs and symptoms of internal bleeding, supplemented by cumulative blood loss assessment performed quantitatively or by visual estimation. Postoperative first response was determined to require an individualised approach.

CONCLUSION

These agreed on proposed approaches could help improve the detection of PPH in the intraoperative and postoperative phases of caesarean birth and the first response management of intraoperative PPH. Determining how best to implement these strategies is a critical next step.

A randomized controlled study comparing oral misoprostol with intramuscular oxytocin in active management of third stage of labour

OBJECTIVE

The study aimed to compare the effectiveness and side effects of 600 μg of oral Misoprostol with 10 international units (IU) intramuscular oxytocin in managing the third stage of labor.

METHODS

This open-label, randomized controlled trial included 260 low-risk women in the second stage of labor with anticipated vaginal delivery. They were randomly assigned, to receive either 600 μg of misoprostol orally or 10 IU of oxytocin intramuscularly. The primary outcomes were blood loss during delivery and incidence of postpartum hemorrhage, evaluated using intention-to-treat analysis. Significance was set at P≤0.05.

RESULTS

Baseline characteristics were similar in both groups (P>0.05). The misoprostol group had a significantly lower blood loss than that of the oxytocin group (306.57±176.44 mL vs. 349.37±135.50 mL; relative difference, -12.251 [95% confidence intervals [CI], -22.528 to -1.575]; P=0.012). Incidence of postpartum hemorrhage was similar in both the groups (relative risk [RR], 0.952 [95% CI, 0.543 to 0.671]; P=0.865). Additional oxytocic therapy requirement was also comparable (RR, 1.143 [95% CI, 0.671 to 1.947]; P=0.623). Nausea, shivering, and mean increase in temperature were significantly more common in the misoprostol group than in the oxytocin-parturient group.

CONCLUSION

In this study, 600 μg oral misoprostol was superior to intramuscular 10 IU oxytocin in reducing blood loss at birth, and equally effective in preventing postpartum hemorrhage. However, misoprostol exhibited more side effects compared to that of oxytocin.

Quantification of blood loss for the diagnosis of postpartum hemorrhage: a systematic review and meta-analysis

OBJECTIVE

to compare the effectiveness of different diagnostic methods to estimate postpartum blood volume loss.

METHODS

a systematic review of effectiveness according to PRISMA and JBI Protocol. Searches in PubMed/MEDLINE, LILACS, Scopus, Embase, Web of Science and CINAHL, with descriptor "Postpartum Hemorrhage" associated with keyword "Quantification of Blood Loss". Tabulated extracted data, presented in metasynthesis and meta-analysis was applied to quantitative data. To assess risk of bias, JBI Appraisal Tools were applied.

RESULTS

fourteen studies were included, published between 2006 and 2021. Quantification of loss by any method was superior to visual estimation and is highly recommended, however the studies' high heterogeneity did not allow estimating this association.

CONCLUSION

the studies' high heterogeneity, with a probable margin of error given the uncontrolled factors, indicates the need for further studies, however quantification proved to be effective in relation to visual estimate. PROSPERO registration CRD 42021234486.

Estimating blood loss during cesarean delivery: A comparison of methods

Objectives

Obstetrical hemorrhage contributes significantly to maternal morbidity and mortality. Assessment of blood loss while undergoing cesarean sections (CS) is essential in lowering the morbidity and mortality, however this amount is commonly underestimated by the surgeon and probably the anesthetist too.

Methods

This study addresses this issue by comparing three separate ways of assessing blood loss during cesarean sections. For each of 97 full-term pregnant women undergoing elective CS, blood loss was measured by the following: visual estimation by both the obstetrician and the anesthetist, weighing surgical pads pre operatively and post operatively and by calculations (multiplying the difference of pre-operative and postoperative hemoglobin values by the patient's estimated blood volume).

Results

The results of this study indicated that the lowest estimated value for blood loss came from visual estimation, while the highest value came from the mathematical formula. Anesthetists were more accurate in their visual estimation of blood loss than were obstetricians.

Conclusion

This study found the amount of blood loss during CS to be overestimated by the mathematical calculation and underestimated by obstetricians. However, the estimate given by anesthetists was close to that obtained by weighing pads. This underscores the need for more accurate methods of blood loss estimation in cesarean sections to be adopted.

Prospective cohort study of induction of labor: Indications, outcome and postpartum hemorrhage

INTRODUCTION

This study was undertaken because of the increasing rate of induction of labor (IOL) in our hospital and its associated higher caesarean section (CS) rates. The objective was to ascertain the incidence, indications, methods, outcome, and complications of IOL, in particular postpartum hemorrhage.

METHODS

This was a prospective observational cohort study of women who underwent IOL in a medium-sized district general hospital. Blood loss was measured by the gravimetric method and correlated to postpartum hemoglobin level within 48 hours of birth.

RESULTS

A total of 445 women needed IOL (incidence 33%). Common indications were: small for gestational age (SGA) or fetal growth restriction (FGR) (18%), spontaneous rupture of membrane (17%), reduced fetal movement (16%), prolonged pregnancy (15%), and diabetes (13%). In all, 67% women achieved spontaneous vaginal delivery and 18% underwent caesarean section. With regard to blood loss, 62 women (14%) had postpartum hemorrhage (PPH) of >1000 mL and 22 women (4.9%) had a blood loss >1500 mL. The caesarean section rate was higher than the overall emergency caesarean section rate in that year. Incidence of PPH in this cohort was higher than the normal incidence.

CONCLUSIONS

Increasing trend of induction of labor (IOL) is due to the changing clinical policy on management of small for gestational age babies, spontaneous rupture of membrane, reduced fetal movement and other complications of pregnancy. There is conflicting evidence on the effect of IOL on caesarean section rates. IOL is a risk factor for PPH. Accurate measurement of blood loss is essential in detecting a fall in hemoglobin which in turn helps in the appropriate management of PPH.

Understanding How Health Providers Identify Women with Postpartum Hemorrhage: A Qualitative Study

OBJECTIVE

 To identify how health providers recognize postpartum hemorrhage early and the difficulties involved in it.

METHODS

 An exploratory, descriptive study using a qualitative approach through a semi-structured interview technique. In total, 27 health professionals (nursing technicians, nurses, medical residents in Gynecology and Obstetrics, hired medical doctors, and medicine professors) working in a tertiary-level hospital of reference in women's health care in the State of São Paulo, Brazil, participated in the study through an invitation. After they accepted the invitation, they signed the free and informed consent form. All interviews were recorded and transcribed, and a thematic analysis was conducted. We found three analysis categories: a) perception of the severity: "there is something wrong with the women"; b) difficulties in the early diagnosis of postpartum hemorrhage; and c) the process to improve obstetrical care.

RESULTS

 Caregivers believe teamwork and communication should be improved. Besides the visual estimation of blood loss, the nursing team is attentive to behavioral symptoms like irritability, while the medical staff follow protocols and look for objective signs, such as altered vital signs.

CONCLUSION

 Besides the objective evaluations, the subjective perceptions of the providers are involved in the clinical judgement regarding the diagnosis of postpartum hemorrhage, and this should be included in a broader diagnosis strategy.

Anesthesia technique and postpartum hemorrhage: a prospective cohort study

Background and objective

During the past few years, an increased number of postpartum hemorrhages have been noticed, even in high-income countries. It has been suggested that this escalation could be associated with increased obstetric interventions. Among such interventions, anesthesia is one of the most prevalent. The present study aimed to investigate the influence of peripartum anesthesia on total blood loss during the 24 hours after delivery.

Methods

We performed a complementary analysis from a prospective cohort study that evaluated postpartum bleeding within 24 hours after birth. The study was performed between February 1^st, 2015 and March 31^st, 2016 at the Women’s Hospital at the Universidade Estadual de Campinas, Brazil. Postpartum bleeding was measured using a calibrated drape and summing the blood contained in the compresses and pads used for 24 hours. We calculated means, percentages, and standard deviation and performed Mann-Whitney analysis for the relation of anesthesia with Postpartum Hemorrhage (PPH) and logistic regression for drugs used in the anesthesia with PPH, using SAS 9.4 software.

Results

We included 270 women in the study; of these, 168 received anesthesia for delivery and almost 50% of them had spinal and epidural anesthesia. The mean blood loss within 24 hours after delivery did not show differences between those who did and those who did not receive obstetrical anesthesia (579.0 ± 361.6 vs. 556.6 ± 360.6; p = 0.57). Logistic regression showed that anesthesia, the type of anesthesia, and the drug used did not influence the PPH above 500 mL and above 1000 mL within 2 hours (p > 0.05).

Conclusion

Anesthesia did not influence postpartum bleeding after vaginal delivery.

Measurement of postpartum blood loss using a new two-set liquid collection bag for vaginal delivery: A prospective, randomized, case control study

BACKGROUND

Postpartum hemorrhage (PPH) is a major obstetric complication, and the real-time measurement of blood loss is important in the management and treatment of PPH. We designed a new two-set liquid collection bag (TSLCB) for measuring postpartum blood loss in vaginal delivery. The aim of this study was to evaluate the effectiveness of the TSLCB in separating the blood from the amniotic fluid during vaginal delivery and in determining the accuracy of the measured postpartum blood loss.

METHODS

A prospective, randomized, case control study was conducted in the Women's Hospital, Zhejiang University School of Medicine, from March 2018 to April 2018. Sixty single pregnant women with spontaneous labor at 37-41 weeks without maternal complications were randomly divided into the experimental and control groups. The TSLCB was used to evaluate separately the amount of blood and amniotic fluid. For the control group, visual estimation and traditional plastic blood-collecting consumables were used to estimate the amount of postpartum blood loss. The measured blood loss between the two groups was compared, and the association of the measured blood loss with various clinical lab indices and vital signs was investigated.

RESULTS

The TSLCB (the experimental group) improved the detection of the measured blood loss compared with visual estimation and the traditional method (the control group) (P < .05). In the experimental group, correlation analysis showed that the measured blood loss at delivery and within 24 h of delivery was significantly associated with the decreased hemoglobin level, red blood cell count, and hematocrit level of patients (r = -0.574, -0.455, -0.437; r = 0.-595, -0.368, -0.374; P < .05). In the control group, only the measured blood loss within 24 h of delivery was associated with the decreased hemoglobin level (r = -0.395, P < .05). No blood transfusion and plasma expanders were required in the treatment of PPH for both groups.

CONCLUSIONS

The TSLCB can be used to accurately measure the postpartum blood loss in vaginal delivery by medical personnel.

The Effect of Rectal Suppository of Anethum graveolens on the Postpartum Hemorrhage Rate: Evidence from a Single-Blind Clinical Trial Study

Background: Postpartum hemorrhage (PPH) is a leading cause of mortality and morbidity worldwide. Anethum graveolens (dill) is one of the recommended herbs to reduce bleeding. Objectives: This study aimed to evaluate the efficacy of rectal suppository of Anethum graveolens on the postpartum hemorrhage (PPH). Methods: Following a randomized clinical design, 70 eligible pregnant women admitted for vaginal delivery to Umm-al-Banin Hospital in Mashhad (Iran) in 2018 were recruited in this trial. Subjects were selected by available method and randomly assigned into two groups of intervention and control. Both groups, immediately after the delivery, received routine hospital interventions. Instantly after the expulsion of the placenta, the intervention group received the first dose of rectal suppository and the subsequent doses up to five doses at intervals of 30 min. PPH was measured by weighing the blood bags and pads for 4h after labor. Data were collected using a sample selection checklist, demographic and pregnancy information forms, birth, infant, and placenta information forms, and partograph sheets. Data were analyzed by SPSS version 22 using an independent t-test or the Mann-Whitney test. Results: The two groups were homogeneous in terms of mediating variables. The mean bleeding rate at the end of the first fourth after delivery was 306.2 ± 11.2 cc in the control group and 282.4 ± 9.6 cc in the intervention group. Therefore, there was a statistically significant difference concerning post-delivery bleeding between the two groups (P = 0.001). Conclusions: Based on the findings, the rectal suppository of Anethum graveolens could effectively reduce the PPH without any adverse effects. Therefore, this efficient herbal approach is suggested to overcome the PPH.

Can measuring blood loss at delivery reduce hemorrhage-related morbidity?

Quantitation of blood loss after vaginal and cesarean delivery has been advocated for the timely detection of postpartum hemorrhage and activation of protocols for resuscitation. Morbidity and mortality from postpartum hemorrhage is considered to be largely preventable and is attributed to delayed recognition with under-resuscitation or inappropriate resuscitation. Optimizing detection of postpartum hemorrhage through refining how blood loss is measured is therefore clinically relevant. In this review on quantitative blood loss for postpartum hemorrhage, recent advances in the methods used to quantitate blood loss will be reviewed, with a comparison of utility and precision for blood loss measurement after vaginal and cesarean delivery. Considerations for the implementation of a quantitative blood loss system on the labor and delivery unit, including its benefits and challenges, will be discussed. The existing evidence for impact of blood loss quantitation in obstetrics on hemorrhage-related morbidity will be delineated, along with knowledge gaps and future research priorities.

Current Challenges in the Peripartum Management of Women with von Willebrand Disease

For many women, pregnancy and childbirth represent their first major hemostatic challenges. Despite advancements in obstetric care, up to 2 to 5% of all deliveries are complicated by postpartum hemorrhage (PPH). To mitigate bleeding risk, physiological changes occur in pregnancy, including increases in plasma von Willebrand factor (VWF) and factor VIII levels. For women with von Willebrand disease (VWD), these physiological alterations are blunted or absent. As a result, women with VWD have a heightened risk of PPH, both primary (in the first 24 hours) and secondary (>24 hours to 6 to 12 weeks postpartum). Pregnancy and delivery management for women with VWD should therefore be carefully coordinated as part of a multidisciplinary team approach. In the absence of large-scale clinical trials, the management of women with VWD during pregnancy is guided by expert consensus guidelines. Clinical practices internationally are not uniform, and areas of considerable clinical uncertainty exist. Traditional peripartum plasma VWF thresholds for hemostatic cover and therapeutic targets are currently under scrutiny, as PPH is not eliminated in women with VWD who receive replacement therapy. The benefit and optimal duration of postpartum tranexamic acid have yet to be defined, and standardized methods of quantification of blood loss at the time of delivery are currently lacking. In this article, we review the evidence base to date and explore the current clinical challenges in the management of pregnant women with VWD.

A review of postpartum hemorrhage in low-income countries and implications for strengthening health systems

Postpartum hemorrhage (PPH) is the leading cause of maternal morbidity and mortality worldwide. Disparities in PPH-associated survival between high and low-/middle-income countries reflect an imperative for low-resource countries to improve strategies for rapid diagnosis and treatment. A review of current PPH diagnosis, prevention, treatment, and access to care in low-income countries has been used to understand, extract, and report the challenges that public health systems face in trying to solve the marked global disparity in PPH outcomes. Improvement in PPH survival begins with holistic strengthening of each step along the continuum of care in health systems and should include performance feedback measures and quality-of-care research.

Do we visually estimate intra-operative blood loss better with white or green sponges and is the deviation from the real blood loss clinically acceptable? Results from a simulated scenario study

BACKGROUND

The intraoperative blood loss is estimated daily in the operating room and is mainly done by visual techniques. Due to local standards, the surgical sponge colours can vary (e.g. white in US, green in Germany). The influence of sponge colour on accuracy of estimation has not been in the focus of research yet.

MATERIAL AND METHODS

A blood loss simulation study containing four "bleeding" scenarios each per sponge colour were created by using expired whole blood donation samples. The blood donations were applied to white and green surgical sponges after dilution with full electrolyte solution. Study participants had to estimate the absorbed blood loss in sponges in all scenarios. The difference to the reference blood loss was analysed. Multivariate linear regression analysis was performed to investigate other influence factors such as staff experience and sponge colour.

RESULTS

A total of 53 anaesthesists participated in the study. Visual estimation correlated moderately with reference blood loss in white (Spearman's rho: 0.521; p = 3.748*10-16) and green sponges (Spearman's rho: 0.452; p = 4.683*10-12). The median visually estimated blood loss was higher in white sponges (250ml IRQ 150-412.5ml) than in green sponges (150ml IQR 100-300ml), compared to reference blood loss (103ml IQR 86-162.8). For both colour types of sponges, major under- and overestimation was observed. The multivariate statistics demonstrates that fabric colours have a significant influence on estimation (p = 3.04*10-10), as well as clinician's qualification level (p = 2.20*10-10, p = 1.54*10-08) and amount of RBL to be estimated (p < 2*10-16).

CONCLUSION

The deviation of correct blood loss estimation was smaller with white surgical sponges compared to green sponges. In general, deviations were so severe for both types of sponges, that it appears to be advisable to refrain from visually estimating blood loss whenever possible and instead to use other techniques such as e.g. colorimetric estimation.

Comparison of common perioperative blood loss estimation techniques: a systematic review and meta-analysis

Estimating intraoperative blood loss is one of the daily challenges for clinicians. Despite the knowledge of the inaccuracy of visual estimation by anaesthetists and surgeons, this is still the mainstay to estimate surgical blood loss. This review aims at highlighting the strengths and weaknesses of currently used measurement methods. A systematic review of studies on estimation of blood loss was carried out. Studies were included investigating the accuracy of techniques for quantifying blood loss in vivo and in vitro. We excluded nonhuman trials and studies using only monitoring parameters to estimate blood loss. A meta-analysis was performed to evaluate systematic measurement errors of the different methods. Only studies that were compared with a validated reference e.g. Haemoglobin extraction assay were included. 90 studies met the inclusion criteria for systematic review and were analyzed. Six studies were included in the meta-analysis, as only these were conducted with a validated reference. The mixed effect meta-analysis showed the highest correlation to the reference for colorimetric methods (0.93 95% CI 0.91–0.96), followed by gravimetric (0.77 95% CI 0.61–0.93) and finally visual methods (0.61 95% CI 0.40–0.82). The bias for estimated blood loss (ml) was lowest for colorimetric methods (57.59 95% CI 23.88–91.3) compared to the reference, followed by gravimetric (326.36 95% CI 201.65–450.86) and visual methods (456.51 95% CI 395.19–517.83). Of the many studies included, only a few were compared with a validated reference. The majority of the studies chose known imprecise procedures as the method of comparison. Colorimetric methods offer the highest degree of accuracy in blood loss estimation. Systems that use colorimetric techniques have a significant advantage in the real-time assessment of blood loss.

Quantification of Intraoperative Blood Loss in a Simulated Scenario Using a Novel Device

BACKGROUND

Particularly for protracted bleeding situations, the realization of a relevant blood loss is necessary for early initiation of therapy to avoid hemodynamic instability and shock. The frequently used visual assessment of blood loss is known to be incorrect. An innovative option to address this problem is a mobile application using colorimetric image correction and analysis.

METHODS

The objective of this study was to evaluate the clinical applicability and accuracy of a novel mobile device application using colorimetric image correction and analysis for blood loss estimation. Scenarios of blood-filled surgical sponges were created to evaluate the accuracy of colorimetric-based blood loss estimation and visual and gravimetric blood loss estimation.

RESULTS

Fifty-three anesthesiologists ran through the scenarios. The estimated blood loss correlated the least with the reference blood loss in the visual technique (Rho: 0.52; P < 3.7×10-16), followed by the gravimetric technique (Rho: 0.73; P = 2.8×10-05). The best correlation was found in the colorimetric blood loss measurement (Rho: 0.77; P = 3.53×10-06). A median overestimation per scenario of 133.0 mL (interquartile range [IQR] 33.0 mL-283.0 mL) was observed when using the visual method, whereas 32.5 mL (IQR 10.8 mL-44.0 mL) was overestimated with the gravimetric method and 31 mL (IQR 17.0 mL-42.8 mL) with the colorimetric method. Especially in the case of blood loss underestimation, the application has the least deviation from the reference.

CONCLUSION

The blood loss measured in the sponges correlated strong with the reference blood loss, showing the smallest median overestimation and the smallest deviation in underestimation. The visual estimation shows serious errors, where the gravimetric method is prone to errors, especially in dilution. The colorimetric method offers an easily implementable possibility to monitor blood loss in real time and to initiate early diagnostic and therapeutic measures in case of persistent blood loss. The influence of real-time estimation of colorimetric blood loss on transfusion decisions should be the subject of future studies.

Methods for blood loss estimation after vaginal birth

BACKGROUND

Almost 358,000 women die each year in childbirth, mainly in low-income countries. More than half of all maternal deaths occur within 24 hours of giving birth; severe bleeding in the postpartum period is the single most important cause. Depending on the rate of blood loss and other factors, such as pre-existing anaemia, untreated postpartum haemorrhage (PPH) can lead to hypovolaemic shock, multi-organ dysfunction, and maternal death, within two to six hours.This review investigated different methods for estimating blood loss. The most common method of measuring blood loss during the third stage of labour is visual estimation, during which the birth attendant makes a quantitative or semi-quantitative estimate of the amount of blood lost. In direct blood collection, all blood lost during the third stage of labour (except for the placenta and membranes) is contained in a disposable, funnelled, plastic collector bag, which is attached to a plastic sheet, and placed under the woman's buttocks. When the bleeding stops, there are two options: the bag can be weighed (also called gravimetric technique), or the bag can be calibrated, allowing for a direct measurement. A more precise measurement of blood loss is haemoglobin concentration (Hb) in venous blood sampling and spectrophotometry. With the dye dilution technique, a known quantity of dye is injected into the vein and its plasmatic concentration is monitored after the uterus stops bleeding. Using nuclear medicine, a radioactive tracer is injected, and its concentration is monitored after the uterus stops bleeding. Although hypothetically, these advanced methods could provide a better quantification of blood loss, they are difficult to perform and are not accessible in most settings.

OBJECTIVES

To evaluate the effect of alternative methods to estimate blood loss during the third stage of labour, to help healthcare providers reduce the adverse consequences of postpartum haemorrhage after vaginal birth.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (2 February 2018), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP; 21 March 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised trials, including cluster-randomised trials, evaluating methods for estimating blood loss after vaginal birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked them for accuracy.

MAIN RESULTS

The search retrieved 62 reports in total. Of these, we assessed 12 reports in full, corresponding to six trials. We included three trials and excluded one; two trials are ongoing.The included trials were conducted in hospital settings. Two trials were conducted in India; the third trial was a large cluster-randomised trial, which took place in 13 European countries. Overall, we judged the included trials to be at a low risk of bias. One study evaluated the use of calibrated drapes versus visual estimation, another evaluated the use of calibrated drapes versus the gravimetric technique (weight of blood-soaked materials), therefore, we were unable to pool the data from the two studies. The third study did not measure any of the outcomes of interest, so did not contribute data to the analyses.Direct measurement using calibrated drapes versus visual estimationOne cluster-randomised controlled trial in 13 western European countries, with over 25,000 women, examined this comparison.The trial did not report on postpartum anaemia (defined as Hb lower than 9 mg/dL), blood loss greater than 500 mL, or maternal infection.Moderate-quality evidence suggests there is probably little or no difference between groups in: severe morbidity (coagulopathy, organ failure, intensive care unit admission; adjusted risk ratio (RR) 0.82, 95% confidence interval (CI) 0.48 to 1.39); the risk of blood transfusion (adjusted RR 0.82, 95% CI 0.46 to 1.46); the use of plasma expanders (adjusted RR 0.77, 95% CI 0.42 to 1.42); and the use of therapeutic uterotonics (adjusted RR 0.87, 95% CI 0.42 to 1.76).Direct measurement using calibrated drapes (Excellent BRASSS-V Drape™) versus gravimetric techniqueOne randomised controlled trial in India, with 900 women, examined this comparison.The trial did not report on postpartum anaemia (defined as Hb lower than 9 mg/dL), severe morbidity, or maternal infection.High-quality evidence showed that using calibrated drapes improved the detection of blood loss greater than 500 mL when compared with the gravimetric technique (RR 1.86, 95% CI 1.11 to 3.11). Low-quality evidence suggests there may be little or no difference in the risk of blood transfusion between the two groups (RR 1.00, 95% CI 0.06 to 15.94), or in the use of plasma expanders, reported as intravenous fluids given for PPH treatment (RR 0.67; 95% CI 0.19 to 2.35). High-quality evidence showed little or no difference in the use of therapeutic uterotonics (RR 1.01, 95% CI 0.90 to 1.13), but the use of therapeutic uterotonics was extremely high in both arms of the study (57% and 56%).

AUTHORS' CONCLUSIONS

Overall, the evidence in this review is insufficient to support the use of one method over another for blood loss estimation after vaginal birth. In general, the quality of evidence for our predefined outcomes ranged from low to high quality, with downgrading decisions due to imprecision. The included trials did not report on many of our primary and secondary outcomes.In trials that evaluate methods for estimating blood loss during vaginal birth, we believe it is important to measure their impact on clinical maternal and neonatal outcomes, along with their diagnostic accuracy. This body of knowledge needs further, well designed, appropriately powered, randomised controlled trials that correlate blood loss with relevant clinical outcomes, such as those listed in this review.

Meconium-stained amniotic fluid: a risk factor for postpartum hemorrhage

Background/aim

Clinical data with respect to the impact of meconium on the risk of maternal hemorrhage are scarce. Therefore, in this study, we aimed to determine whether meconium-stained amniotic fluid (MSAF) represents a risk factor for postpartum hemorrhage (PPH) after vaginal delivery in a large unselected population.

Patients and methods

A retrospective cohort study evaluated 78,542 consecutive women who had a vaginal delivery between 24th and 44th weeks of gestation. The women who had undergone cesarean section were excluded to avoid possible bias. Postpartum blood loss was measured with graduated blood sack. Postpartum blood loss between 1,000 and 2,000 mL and >2,000 mL were classified as moderate and severe PPH, respectively.

Results

A total of 74,144 patients were available for analysis. According to the color of amniotic fluid (AF), two groups of patients were identified: MSAF (n=10,997) and clear AF (n=63,147). The rates of severe and massive PPH were found to be significantly higher in the MSAF group than that of clear AF group (OR=1.3, 95% CI: 1.2-1.5, p<0.001 and OR=2.5, 95% CI: 1.5-4.2, p<0.001). Operative vaginal delivery rate was found to be higher in the MSAF group than that of clear AF group, but the difference was only borderline significant (OR=1.5, 95% CI: 1.0-2.2, p=0.05). There were no significant differences between the MSAF and the clear AF groups with respect to episiotomies, second- or third-degree perineal tears, vaginal-perineal thrombus, cervical lacerations, vaginal births after cesarean section, twin deliveries, and placental retention rates.

Conclusion

To the best of our knowledge, this is the first clinical study that has investigated the role of MSAF as a risk factor for PPH after vaginal delivery in an unselected population. Our results suggest that MSAF is significantly associated with higher risk of moderate and severe PPH than clear AF.

Postpartum hemorrhage: new insights for definition and diagnosis

The current definition of is inadequate for early recognition of this important cause of maternal death that is responsible for >80,000 deaths worldwide in 2015. A stronger definition of postpartum hemorrhage should include both blood loss and clinical signs of cardiovascular changes after delivery, which would help providers to identify postpartum hemorrhage more promptly and accurately. Along with the amount of blood loss, clinical signs, and specifically the shock index (heart rate divided by systolic blood pressure) appear to aid in more accurate diagnosis of postpartum hemorrhage.

Measuring Post-Partum Haemorrhage in Low-Resource Settings: The Diagnostic Validity of Weighed Blood Loss versus Quantitative Changes in Hemoglobin

Background

Accurate estimation of blood loss is central to prompt diagnosis and management of post-partum hemorrhage (PPH), which remains a leading cause of maternal mortality in low-resource countries. In such settings, blood loss is often estimated visually and subjectively by attending health workers, due to inconsistent availability of laboratory infrastructure. We evaluated the diagnostic accuracy of weighed blood loss (WBL) versus changes in peri-partum hemoglobin to detect PPH.

Methods

Data from this analysis were collected as part of a randomized controlled trial comparing oxytocin with misoprostol for PPH (NCT01866241). Blood samples for complete blood count were drawn on admission and again prior to hospital discharge or before blood transfusion. During delivery, women were placed on drapes and had pre-weighed sanitary towels placed around their perineum. Blood was then drained into a calibrated container and the sanitary towels were added to estimate WBL, where each gram of blood was estimated as a milliliter. Sensitivity, specificity, negative and positive predictive values (PPVs) were calculated at various blood volume loss and time combinations, and we fit receiver-operator curves using blood loss at 1, 2, and 24 hours compared to a reference standard of haemoglobin decrease of >10%.

Results

A total of 1,140 women were enrolled in the study, of whom 258 (22.6%) developed PPH, defined as a haemoglobin drop >10%, and 262 (23.0%) had WBL ≥500mL. WBL generally had a poor sensitivity for detection of PPH (<75% for most volume-time combinations). In contrast, the specificity of WBL was high with blood loss ≥ 500mL at 1h and ≥750mL at any time points excluding PPH in over 97% of women. As such, WBL has a high PPV (>85%) in high prevalence settings when WBL exceeds 750mL.

Conclusion

WBL has poor sensitivity but high specificity compared to laboratory-based methods of PPH diagnosis. These characteristics correspond to a high PPV in areas with high PPH prevalence. Although WBL is not useful for excluding PPH, this low-cost, simple and reproducible method is promising as a reasonable method to identify significant PPH in such settings where quantifiable red cell indices are unavailable.