Modified early obstetric warning scores: A promising tool but more evidence and standardization is required

Predicting intensive care need in women with preeclampsia using machine learning - a pilot study

BACKGROUND

Predicting severe preeclampsia with need for intensive care is challenging. To better predict high-risk pregnancies to prevent adverse outcomes such as eclampsia is still an unmet need worldwide. In this study we aimed to develop a prediction model for severe outcomes using routine biomarkers and clinical characteristics.

METHODS

We used machine learning models based on data from an intensive care cohort with severe preeclampsia (n=41) and a cohort of preeclampsia controls (n=40) with the objective to find patterns for severe disease not detectable with traditional logistic regression models.

RESULTS

The best model was generated by including the laboratory parameters aspartate aminotransferase (ASAT), uric acid and body mass index (BMI) with a cross-validation accuracy of 0.88 and an area under the curve (AUC) of 0.91. Our model was internally validated on a test-set where the accuracy was lower, 0.82, with an AUC of 0.85.

CONCLUSION

The clinical routine blood parameters ASAT and uric acid as well as BMI, were the parameters most indicative of severe disease. Aspartate aminotransferase reflects liver involvement, uric acid might be involved in several steps of the pathophysiologic process of preeclampsia, and obesity is a well-known risk factor for development of both severe and non-severe preeclampsia likely involving inflammatory pathways..[Figure: see text].

Maternal Complications After Laser Surgery for Twin-to-Twin Transfusion Syndrome, a Cohort Study

OBJECTIVES

To assess maternal complications after fetoscopic laser surgery (FLS) for the twin-to-twin transfusion syndrome (TTTS).

METHODS

All consecutive cases treated with FLS for TTTS between 2008 and 2021 at the Leiden University Medical Center (LUMC) were included. We allocated complications in three timeframes: "Admission for laser surgery," "pregnancy after laser," and "delivery and third stage of labor." Maternal complications were graded according to the Maternal and Fetal Adverse Event Terminology (MFAET) and for intra-abdominal hemorrhage, the Common Terminology Criteria for Adverse Events (CTCAE).

RESULTS

In the study period, 637 mothers were treated for TTTS with FLS. There were 1559 occurrences of maternal complications. The rate of severe maternal complications (grade 3 or 4) was 8.0%. Severe complications consisted of six cases of severe intra-abdominal hemorrhage, nine cases of severe hemorrhage in pregnancy, one with severe chorioamnionitis, 10 with severe preeclampsia/HELLP syndrome, and 25 with a severe postpartum hemorrhage.

CONCLUSIONS

Even though it is the gold standard for treating TTTS, FLS comes at a risk to the mother which should not be neglected. And even though not all complications have serious consequences to the mother, the severe maternal complication rate of 8.0% should be added to the inherent risks for the fetus, and should be discussed with patients eligible for surgery in order to make an informed decision on treatment options.

Preparedness for severe maternal morbidity in European hospitals: The MaCriCare study

PURPOSE

To evaluate obstetric units (OUs) and intensive care units (ICUs) preparedness for severe maternal morbidity (SMM).

METHODS

From September 2021 to January 2022, an international multicentre cross-sectional study surveyed OUs in 26 WHO Europe Region countries. We assessed modified early obstetric warning score usage (MEOWS), approaches to four SMM clinical scenarios, invasive monitoring availability in OUs, and access to high-dependency units (HDUs) and onsite ICUs. Within ICUs, we examined the availability of trained staff, response to obstetric emergencies, leadership, and data collection.

RESULTS

1133 responses were evaluated. MEOWS use was 34.5%. Non-obstetric early warning scores were being used. 21.4% (242) of OUs provided invasive monitoring in the OU. A quarter lacked access to onsite HDU beds. In cases of SMM, up to 13.8% of all OUs indicated the need for transfer to another hospital. The transfer rate was highest (74.0%) in small units. 81.9% of centers provided onsite ICU facilities to obstetric patients. Over 90% of the onsite ICUs provided daily specialist obstetric reviews but lacked immediate access to key resources: 3.4% - uterotonic drugs, 7.5% - neonatal resuscitation equipment, 9.2% - neonatal resuscitation team, 11.4% - perimortem cesarean section equipment. 41.2% reported obstetric data to a national database.

CONCLUSION

Gaps in provision exist for obstetric patients with SMM in Europe, potentially compromising patient safety and experience. MEOWS use in OUs was low, while access to invasive monitoring and onsite HDU and ICU facilities was variable. ICUs frequently lacked resources and did not universally collect obstetric data for quality control.

Development of a national maternity early warning score: centile based score development and Delphi informed escalation pathways

Objective

To derive a new maternity early warning score (MEWS) from prospectively collected data on maternity vital signs and to design clinical response pathways with a Delphi consensus exercise.

Design

Centile based score development and Delphi informed escalation pathways.

Setting

Pregnancy Physiology Pattern Prediction (4P) prospective UK cohort study, 1 August 2012 to 28 December 2016.

Participants

Pregnant people from the 4P study, recruited before 20 weeks' gestation at three UK maternity centres (Oxford, Newcastle, and London). 841, 998, and 889 women provided data in the early antenatal, antenatal, and postnatal periods.

Main outcome measures

Development of a new national MEWS, assigning numerical weights to measurements in the lower and upper extremes of distributions of individual vital signs from the 4P prospective cohort study. Comparison of escalation rates of the new national MEWS with the Scottish and Irish MEWS systems from 18 to 40 weeks' gestation. Delphi consensus exercise to agree clinical responses to raised scores.

Results

A new national MEWS was developed by assigning numerical weights to measurements in the lower and upper extremes (5%, 1%) of distributions of vital signs, except for oxygen saturation where lower centiles (10%, 2%) were used. For the new national MEWS, in a healthy population, 56% of observation sets resulted in a total score of 0 points, 26% a score of 1 point, 12% a score of 2 points, and 18% a score of ≥2 points (escalation of care is triggered at a total score of ≥2 points). Corresponding values for the Irish MEWS were 37%, 25%, 22%, and 38%, respectively; and for the Scottish MEWS, 50%, 18%, 21%, and 32%, respectively. All three MEWS were similar at the beginning of pregnancy, averaging 0.7-0.9 points. The new national MEWS had a lower mean score for the rest of pregnancy, with the mean score broadly constant (0.6-0.8 points). The new national MEWS had an even distribution of healthy population alerts across the antenatal period. In the postnatal period, heart rate threshold values were adjusted to align with postnatal changes. The centile based score derivation approach meant that each vital sign component in the new national MEWS had a similar alert rate. Suggested clinical responses to different MEWS values were agreed by consensus of an independent expert panel.

Conclusions

The centile based MEWS alerted escalation of care evenly across the antenatal period in a healthy population, while reducing alerts in healthy women compared with other MEWS systems. How well the tool predicted adverse outcomes, however, was not assessed and therefore external validation studies in large datasets are needed. Unlike other MEWS systems, the new national MEWS was developed with prospectively collected data on vital signs and used a systematic, expert informed process to design an associated escalation protocol.

Obstetric infections and clinical characteristics of maternal sepsis: a hospital-based retrospective cohort study

Sepsis is responsible for 50% of intrahospital maternal deaths worldwide. Incidence is increasing in both low and middle-, and high-income countries. There is little data on incidence and clinical outcomes of obstetric infections including maternal sepsis in the Nordic countries. The aims of this study are to give estimates of the occurrence of obstetric infections and maternal sepsis in a Norwegian hospital cohort, assess the quality of management of maternal sepsis cases, and evaluate the usefulness of diagnostic codes to identify maternal sepsis retrospectively. We conducted a retrospective cohort study of pregnant, labouring, post-abortion, and postpartum women. We assessed the accuracy of the diagnostic code most frequently applied for maternal sepsis, O85. We found 7.8% (95% confidence interval 7.1-8.5) infection amongst pregnant, labouring, and postpartum women. The incidence of maternal sepsis was 0.3% (95% confidence interval 0.2-0.5), and the majority of sepsis cases were recorded in the postpartum period. Two thirds of women were given broad-spectrum antibiotics at the time sepsis was diagnosed, but only 15.4% of women with puerperal sepsis were given antimicrobials in accordance with national guidelines. When used retrospectively, obstetric infection codes are insufficient in identifying both maternal and puerperal sepsis, with only 20.3% positive predictive value for both conditions. In conclusion, obstetric infections contribute significantly to maternal morbidity in Norway's second largest maternity hospital. This study provides incidences of maternal infections for hospitalised patients in temporal relation to pregnancy, labour, abortion and the postpartum period, knowledge which is valuable for planning of health care services and allocation of resources. In addition, the study highlights areas where improvement is needed in clinical handling of maternal sepsis. There is need for studies on the management quality and use of correct diagnostic codes in this patient category.

Evaluating the performance of the National Early Warning Score in different diagnostic groups

BACKGROUND

The National Early Warning Score (NEWS) is used in hospitals across the UK to detect deterioration of patients within care pathways. It is used for most patients, but there are relatively few studies validating its performance in groups of patients with specific conditions.

METHODS

The performance of NEWS was evaluated against 36 other Early Warning Scores, in 123 patient groups, through use of the area under the receiver operating characteristic (AUROC) curve technique, to compare the abilities of each Early Warning Score to discriminate an outcome within 24hrs of vital sign recording. Outcomes evaluated were death, ICU admission, or a combined outcome of either death or ICU admission within 24 hours of an observation set.

RESULTS

The National Early Warning Score 2 performs either best or joint best within 120 of the 123 patient groups evaluated and is only outperformed in prediction of unanticipated ICU admission. When outperformed by other Early Warning Scores in the remaining 3 patient groups, the performance difference was marginal.

CONCLUSIONS

Consistently high performance indicates that NEWS is a suitable early warning score to use for all diagnostic groups considered by this analysis, and patients are not disadvantaged through use of NEWS in comparison to any of the other evaluated Early Warning Scores.

Carle's obstetric early warning score as a screening tool for critical care admission

BACKGROUND OBJECTIVES

Early warning systems (EWS) involve serial observations (track) with criteria (trigger) to timely identify patients at risk of complications. Carle designed a statistically based clinically modified obstetric early warning score (Carle's OEWS). This study evaluated Carle's OEWS and its individual components for predicting admission to the obstetric critical care unit (OCCU). Maternal near-miss and maternal mortality were the secondary outcomes.

METHODS

A prospective observational study was conducted among 1250 pregnant women with a period of gestation ≥28 week admitted in the labour wards of a tertiary centre over 18 months. The physiological parameters of OEWS were recorded and aggregate score was calculated at admission and at regular intervals thereafter, till discharge or OCCU admission.

RESULTS

The area under receiver operating characteristic (ROC) curve of OEWS was 0.975 for predicting OCCU admission, 0.971 for near-miss, and 0.996 for predicting maternal mortality and was significant for all outcomes. All individual parameters, except diastolic blood pressure, had a significant relative risk for predicting OCCU requirement.

INTERPRETATION CONCLUSIONS

Carle's OEWS is a useful screening tool for predicting obstetric OCCU admission and can be routinely used in labour wards to ensure timely intervention.

Application of the Modified Early Obstetrical Warning System (MEOWS) in postpartum patients in the emergency department

INTRODUCTION

Over the last two decades, there has been a steady rise in severe maternal morbidity and pregnancy-related deaths in Canada and the USA. The Modified Early Obstetric Warning System (MEOWS) is a risk stratification tool designed to predict severe maternal morbidity and mortality and has been validated for use in obstetrical wards. The objective of this study was to determine if MEOWS could accurately identify patients at risk of severe maternal morbidity and mortality in the ED setting.

METHODS

This was a chart review of patients presenting to an academic tertiary care centre (annual ED census 65,000) with a postpartum complaint within 6 weeks of delivery between May 2020 and March 2022. The exposure was the presence of a trigger, defined as one severely abnormal (red) or two mildly abnormal (yellow) physiological measurements during the ED visit. The diagnostic accuracy of the tool to identify patients at risk of severe maternal morbidity severe maternal morbidity or mortality was estimated by calculating the sensitivity, specificity, positive predictive value and negative predictive value.

RESULTS

Two hundred and sixty-seven patients were included, of which 21 (7.9%) met the criteria for severe maternal morbidity. There were no maternal deaths. Overall, the sensitivity of the MEOWS tool was 85.7% (95% CI 63.7-97.0%), specificity was 67.9% (95% CI 61.7-73.7%), positive predictive value was 18.6% (95% CI 15.1-22.7%), and negative predictive value was 98.2% (95% CI 95.1-99.4%). Severe preeclampsia and eclampsia were the most common outcome category of severe maternal morbidity, representing 16 (76.2%) cases. Most patients (86.5%) were discharged directly from the ED, and 90.0% did not return within 30 days.

CONCLUSIONS

This study is the first to explore the utility of MEOWS in postpartum ED patients. The presence of a MEOWS trigger at ED triage or the first ED nursing assessment was associated with severe maternal morbidity. Thus, MEOWS may be a valuable tool to identify postpartum patients at risk of severe outcomes early in an ED visit.

Maternal collapse in pregnancy

Maternal collapse is a rare life-threatening event that can occur at any stage of pregnancy or up to 6 weeks postpartum. Prompt identification and timely intervention by a multidisciplinary team that includes an obstetrician, midwifery staff and an obstetric anaesthetist are essential to improve maternal and fetal outcomes. Standard adult resuscitation guidelines need to be followed with some modifications, taking into account the maternal-fetal physiology, which clinicians should be familiar with. During cardiac arrest, the emphasis is on advanced airway management, manual uterine displacement to relieve aortocaval compression and performing a resuscitative hysterotomy (peri-mortem caesarean delivery) swiftly in patients who are more than 20 weeks gestation to improve maternal survival. Annual multidisciplinary simulation training is recommended for all professionals involved in maternity care; this can improve teamwork, communication and emergency preparedness during maternal collapse.

Identifying interventions to reduce peripartum haemorrhage associated with caesarean delivery in Africa: A Delphi consensus study

Women in Africa are fifty times more likely than in high-income settings to die following caesarean delivery, and peripartum haemorrhage is most strongly associated with mortality. We aimed to establish consensus on which interventions are considered most feasible to implement and most effective at reducing haemorrhage associated with caesarean delivery across Africa. We conducted a Delphi consensus study, including obstetric and anaesthesia providers from across Africa. In round one the expert group proposed key interventions for consideration. In rounds two and three the interventions were ranked on a 9-point Likert scale for effectiveness and feasibility. Round four was an online discussion to establish consensus on effectiveness and feasibility of interventions for which this had not been reached in round three. Twenty-eight interventions were considered both highly effective and feasible in Africa. Interventions covered a range of fields, categorised into direct- or indirect interventions. Direct interventions included: risk assessment and screening; checklists and protocols; monitoring and surveillance; availability of resources; ability to perform technical skills. Indirect interventions included: community and maternal education; contraception and family planning; minimum training standards; referral patterns and delays; advocacy to key stakeholders; simulation and team training; and 24-hour access to safe emergency caesarean delivery. Interventions considered both effective and feasible in reducing peripartum haemorrhage associated with caesarean delivery in Africa were identified. A multi-layered implementation strategy, including immediately developing a perioperative caesarean delivery bundle of care, in addition to longer-term public health measures may have a profound impact on maternal mortality in Africa.

Midwives' recognition and response to maternal deterioration: A national cross-sectional study

BACKGROUND

Early warning systems (EWS) are used across health care settings as a tool for the early identification of clinical deterioration and to determine the need to escalate care. Early detection of clinical deterioration and appropriate escalation of care in maternity settings is critical to the safety of pregnant women and infants; however, underutilization of EWS tools and reluctance to escalate care have been consistently reported. Little is known about midwives' use of EWS in the Australian context.

METHODS

Using a cross-sectional approach, we elicited the attitudes, beliefs, and behaviors of a purposive sample of Australian midwives (n = 87) with respect to the Maternal Early Warning Trigger Tool (MEWT). Participants answered a 25-question Likert scale survey and one open-ended question. Qualitative answers were analyzed using consensus coding.

RESULTS

Midwives reported positive attitudes toward the MEWT, describing it as a valuable tool for identifying clinical deterioration, especially when used as an adjunct to clinical judgment. However, midwives also identified training gaps; 25% had received no training, and only half of those who had received training felt it was effective. In addition, professional tension can create a significant barrier to the effective use of the MEWT. Midwives also reported feeling influenced by their peers in their decision-making with respect to use of the MEWT and being afraid they would be chastised for escalating care unnecessarily.

CONCLUSIONS

Although the MEWT is valued by Australian midwives as a useful tool, barriers exist to its effective use. These include a lack of adequate, ongoing training and professional tension. Improving interdisciplinary collaboration could enhance the use of this tool for the safety of birthing women and their infants.

Early warning systems in maternity care: A qualitative evidence synthesis of maternity care providers' views and experiences

OBJECTIVE

To gain insight and understanding, from the perspective of maternity care providers, on the use and application of maternity early warning systems (MEWS) in clinical practice.

DESIGN

A qualitative evidence synthesis was conducted. MEDLINE, CINHAL, Web of Science Core Collection and Maternity and Infant Care (MIDIRS), from inception to March 2021, were searched for eligible studies. Grey literature sources were also searched for unpublished studies. The methodological quality of included studies was assessed by at least two reviewers using an Evidence for Policy and Practice Information and Co-ordinating (EPPI) Centre quality assessment tool. Thomas and Harden's thematic synthesis approach was used to guide the data synthesis. Confidence in the findings was assessed using the Grading of Recommendations Assessment, Development and Evaluation of Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual).

SETTING AND PARTICIPANTS

Included studies reported on maternity care providers involved in caring for pregnant or postpartum women in any birth setting. Studies were mostly qualitative in design, although survey designs with open-ended questions that provided qualitative data were eligible for inclusion if the qualitative data had been subjected to formal analyses.

FINDINGS

Eight eligible studies, reported across nine records, were identified in the search and included in the review. Three themes representative of maternity care providers' views and experiences of MEWS were generated from the synthesis. These were 'Aid to clinical care provision', 'Impact on workload' and 'Factors affecting MEWS implementation'. MEWS was viewed as a useful tool in guiding clinical care, and for identifying deterioration and the need to escalate care. Some maternity care providers viewed MEWS as beneficial in easing workload burden. Others, however, viewed MEWS as adding to workload because of repetition and duplication. Training in MEWS was considered inadequate and concern existed for some care providers that MEWS would lead to deskilling or eroding of professional judgement.

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Maternity care providers hold diverse views on the use of MEWS in clinical practice. While almost all consider MEWS a helpful aid for guiding clinical care, barriers to implementation were identified. These included added workload burden, inadequate training, and concern for deskilling. Attending to implementation barriers will help optimise use of MEWS in clinical practice as currently recommended.

Managing COVID-19 in pregnant women

Principles of management of COVID-19 in the general population apply in pregnancy with few exceptions. Clinical inertia can lead to preventable morbidity and mortality. COVID-19 vaccines are safe and should be recommended at any stage of pregnancy. https://bit.ly/3Rj8nWr.

Management of Isolated Fever in Labour Compared with Clinical Chorioamnionitis in a Quaternary Centre

OBJECTIVES

To investigate treatment patterns of women with isolated fever in labour and evaluate if variables in the sepsis in obstetrics score (SOS) or fetal tachycardia are associated with treatment differences. Our secondary objective was to compare women with isolated fever in labour with women with clinical chorioamnionitis to identify any clinicodemographic differences.

METHODS

A retrospective cohort study of 473 patients at BC Women's Hospital who presented with isolated fever in labour between January 2011 and April 2016 compared with a dataset of 1135 women with clinical chorioamnionitis from 2011 to 2016 in the same institution.

RESULTS

In our cohort of isolated fever in labour, antibiotics were given 74.2 % of the time, and the majority received cefazolin and metronidazole (80.9%, of those who received antibiotics). Higher maternal temperature and heart rate at time of first fever and fetal tachycardia were associated with more antibiotic use. Slightly higher maternal temperature was associated with use of a saline bolus and blood cultures. The proportion of women with a SOS greater than 5 increased 4.5-fold from time of first fever to time of maximum SOS. There were fewer cesarean deliveries in the isolated fever in labour group compared with the clinical chorioamnionitis group (22.4% vs. 54.0%; P < 0.0001).

CONCLUSIONS

Slightly higher maternal temperature was associated with increased treatment, including antibiotic use, saline bolus administration, and blood cultures. As evidenced by the higher proportion of women with an SOS over 5, women with isolated fever in labour may have a propensity to deteriorate clinically.

Improving assessment of acute obstetric patients - introducing a Swedish obstetric triage system

BACKGROUND

Failure to identify severely ill obstetric patients seeking acute care, and hence delaying treatment, can lead to maternal morbidity and mortality. Triage is the prioritization of patients seeking emergency care, based on clinical decision-making tools assessing medical urgency. While triage has been applied in general emergency medicine for 30 years, there are only a few obstetric triage systems (OTS) and obstetric triage has hitherto been unknown in Sweden. Obstetric triage is more complex than general triage since both mother and fetus require assessment, and pregnancy-related physiological changes must be taken into account. This paper aims to describe the development and an initial evaluation of the first OTS in Sweden.

METHODS

A multidisciplinary team surveyed reasons to seek acute obstetric care and the current patient flow at the largest obstetric unit in Scandinavia, Sahlgrenska University Hospital, Gothenburg, Sweden, with about 10,000 deliveries/year. A semi-structured literature review on obstetric triage was undertaken. Based on the survey and the literature review the first Swedish OTS was developed and implemented. Patient satisfaction was followed by electronical questionnaires. Initial validity evaluation was performed, defined by the system's ability to identify patients with need for hospital admission, stratified by acuity level.

RESULTS

The Gothenburg Obstetrical Triage System (GOTS) addresses the patient to one of five acuity levels based on both vital signs and 14 chief complaint algorithms. It entails recommendations for initial procedures of care as well as an acuity form for documentation. Initial evaluation of the system indicates good correlation between need for admission and acuity level. The implementation has provided the staff with an improved medical overview of the patients and patient flow and enabled the unit to monitor emergency care in a structured way. Implementation came along with increased patient and staff satisfaction.

CONCLUSION

The GOTS is the first OTS developed in and for Sweden and implementation has improved management of obstetric patients seeking acute care. Patients are now prioritized according to level of acuity and the time to assessment and treatment of severely ill patients can be structurally evaluated. Both patients and staff express improved satisfaction with obstetric triage.

An interrater reliability study on the Gothenburg obstetric triage system- a new obstetric triage system

BACKGROUND

Triage, identifying patients with critical and time-sensitive disorders, is an integrated process in general emergency medicine. Obstetric triage is more specialised, requiring assessment of both woman, fetus and labour status. Failure to identify severely ill obstetric patients has repeatedly led to maternal morbidity and mortality. Reliable triage systems, adapted to obstetric patients as well as local conditions, are thus essential. The study aims to assess the interrater reliability (IRR) of the Gothenburg Obstetric Triage System (GOTS).

METHODS

Midwives (n = 6) and registered nurses with no experience in managing obstetric patients (n = 7), assessed 30 paper cases based on actual real-life cases, using the GOTS. Furthermore, a reference group consisting of two midwives and two obstetricians, with extensive experience in obstetric care, determined the correct triage level in order to enable analysis of over- and undertriage. IRR was assessed, both with percentage of absolute agreement and with intra-class correlation coefficients (ICC) with 95% confidence intervals (CI).

RESULTS

A total of 388 assessments were performed, comprising all five levels of acuity in the GOTS. Absolute agreement was found in 69.6% of the assessments. The overall IRR was good, with a Kappa value of 0.78 (0.69-0.87, 95% CI) for final triage level. Comparison with reference group assessments established that over- and undertriage had occurred in 9% and 21% of the cases, respectively. The main reasons for undertriage were "not acknowledging abnormal vital sign parameters" and "limitations in study design".

CONCLUSION

The GOTS is a reliable tool for triaging obstetric patients. It enables a standardized triage process unrelated to the assessors' level of experience in assessing and managing obstetric patients and is applicable for triaging obstetric patients presenting for emergency care at obstetric or emergency units.

Early warning systems in maternity care: protocol for a qualitative evidence synthesis of maternity care providers' views and experiences

Background: Early warning systems (EWS) have been widely adopted for use in maternity settings internationally. The idea in using these systems is early recognition of potential or actual clinical deterioration in pregnant or postpartum women, and escalation of care. Barriers to successful implementation and use of EWS, however, have been identified. If EWS are to be applied consistently, a greater understanding of the views and experiences of EWS from the perspectives of those using and applying EWS in maternity practice is needed. This protocol describes a qualitative evidence synthesis of maternity care providers' (midwives, obstetricians, and allied maternity care professionals) views and experiences of EWS use and application in practice. Methods: Studies will be included in the review if they report on maternity care providers use and application of EWS in any birth setting. Qualitative studies and studies of mixed methods design, where qualitative data can be extracted separately, will be included. To source relevant literature the electronic databases of MEDLINE, CINHAL, Web of Science Core Collection (incorporating Social Science Citation Index) and Maternity and Infant Care (MIDIRS), from date of inception, will be searched. The methodological quality of the included studies will be appraised using the 12-criteria of the assessment tool developed by the Evidence for Policy and Practice Information and Co-ordinating Centre. Thematic synthesis will be used for synthesising the qualitative data from included studies. The confidence in the findings will be assessed using the Grading of Recommendations Assessment, Development and Evaluation-Confidence in the Evidence from Reviews of Qualitative research. Conclusions: The findings of this qualitative evidence synthesis may provide valuable information on the barriers, challenges, and facilitators for EWS use based on the experiences of those directly involved in EWS application in maternity care provision. PROSPERO registration: CRD42021235137 (08/04/2021).

Modified early obstetric warning scores: A promising tool but more evidence and standardization is required

Early warning systems involve the routine monitoring and recording of vital signs or clinical observations on specifically designed charts with linked escalation protocols. Meeting criteria for abnormal physiological parameters triggers a color-coded or weighted scoring system aimed to guide the frequency of monitoring, need for, and urgency of clinical review. Color-coded systems trigger a clinical response when one or more abnormal observation is recorded in the red zone or two or more mildly abnormal parameters in the amber zone. The principle of maternity-specific early warning systems to structure surveillance for hospitalized women is intuitive. The widespread use and policy support, including recommendations following confidential enquiries and from the National Health Service Litigation Authority, is not, however, currently backed up by a strong evidence base. Research is required to develop predictive models and validate evidence-based maternity-specific early warning systems in the general maternity population.