Objective To review what is known about the relationship between stillbirth and inequalities from different disciplinary perspectives to inform stillbirth prevention strategies.
Design Systematic review using the meta-narrative method.
Setting Studies undertaken in the UK.
Data sources Scoping phase: experts in field, exploratory electronic searches and handsearching. Systematic searches phase: Nine databases with no geographical or date restrictions. Non-English language studies were excluded.
Study selection Any investigation of stillbirth and inequalities with a UK component.
Data extraction and synthesis Three authors extracted data and assessed study quality. Data were summarised, tabulated and presented graphically before synthesis of the unfolding storyline by research tradition; and then of the commonalities, differences and interplays between narratives into resultant summary meta-themes.
Results Fifty-four sources from nine distinctive research traditions were included. The evidence of associations between social inequalities and stillbirth spanned 70 years. Across research traditions, there was recurrent evidence of the social gradient remaining constant or increasing, fuelling repeated calls for action (meta-theme 1: something must be done). There was less evidence of an effective response to these calls. Data pertaining to socioeconomic, area and ethnic disparities were routinely collected, but not consistently recorded, monitored or reported in relation to stillbirth (meta-theme 2: problems of precision). Many studies stressed the interplay of socioeconomic status, deprivation or ethnicity with aggregated factors including heritable, structural, environmental and lifestyle factors (meta-theme 3: moving from associations towards intersectionality and intervention(s)). No intervention studies were identified.
Conclusion Research investigating inequalities and stillbirth in the UK is underdeveloped. This is despite repeated evidence of an association between stillbirth risk and poverty, and stillbirth risk, poverty and ethnicity. A specific research forum is required to lead the development of research and policy in this area, which can harness the multiple relevant research perspectives and address the intersections between different policy areas.
PROSPERO registration number CRD42017079228.
- social class
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Strengths and limitations of this study
Meta-narrative is a systematic methodological approach to understand how multiple disciplines and different philosophical perspectives have researched a question over time.
This study used a meta-narrative approach to investigate the association between inequalities and stillbirth in the UK.
We adhered to the RAMESES standards for meta-narrative reviews to ensure fidelity with the methodology.
We used a multipronged approach to retrieving sources that included exploratory searches, systematic searches hand searches, expert opinion, and forward and back-chaining.
By limiting the review to UK-based studies only, we were able to focus with greater acuity on the commonalities and contestations between research traditions, but this may have led us to miss important research on the association between stillbirth and inequalities from other countries, of relevance both in the UK context and globally.
Avoidable inequalities in mortality across the life course are a global concern.1 Ten countries account for 66% of the world’s stillbirths, with most (98%) occurring in low-income and middle-income countries.2 Inequalities exist within and between high-income countries (HICs) too. In 2011, The Lancet Stillbirth Series highlighted that the UK’s stillbirth rate was one of the highest of all HICs.3 In 2016, the second Lancet Series Ending Preventable Stillbirths reported that while overall stillbirth rates were falling in HICs, improvement was slower than expected, and significant inequalities within rates remained.4 The UK’s stillbirth rate continues to remain high in comparison to other HICs.5
The government’s ambition is to halve the stillbirth rate in England by 2025, which would require the rate to fall to 2.6 per 1000 total births.6 In 2017, the stillbirth rate in England and Wales was to 4.2 per 1000 total births.7 Medical reasons for stillbirth are well known and strategies for prevention routine. Ongoing initiatives include the Safer Maternity Care strategic plan,8 Saving Babies Lives Care Bundle,9 Each Baby Counts,10 the Perinatal Mortality Review Tool11 and annual Perinatal Mortality Reports (MBRRACE-UK).5 The association between social determinants and stillbirth is less well understood. Clinicians acknowledge the need to do more to prevent stillbirth in women from socially disadvantaged groups. In England, in 2017, the stillbirth rate in the most deprived areas was 5.5 per 1000 total births, compared with 3.0 per 1000 total births in the least deprived areas.7
The UK began to develop policies to address health inequalities in general following The Acheson Inquiry into Inequalities in Health.12 The Marmot Review Fair Society, Healthy lives, published in 2010, progressed the UK’s inequalities agenda by emphasising the importance of taking a life-course approach, starting with the early years and family building.13 The key messages of the Marmot Review emphasised that there is a social gradient in health in the UK, whereby the lower an individual’s social position the worse his or her health, which is unfair, and that this requires action across all the social determinants of health.
Public Health England’s current strategy for action on inequalities Reducing health inequalities: system, scale and sustainability14 is underpinned by the Dahlgren and Whitehead rainbow model of the social determinants of health.15 This model offers a framework to explore the relative influence of these determinants on different health outcomes and the interactions between the various determinants. These are all potential mechanisms by which stillbirth risk maybe increased. What is missing from current stillbirth research agendas is an overarching synthesis of clinical and social science evidence to clarify the range of individual (including biological and behavioural), social and environmental mechanisms of increased stillbirth risk, the intersections between these mechanisms and strategies to tackle them. This review sought to fill this knowledge gap.
We undertook an interdisciplinary evidence synthesis (using a meta-narrative approach) to understand how structural factors, lifestyle factors and clinical factors intersect to increase stillbirth risk, and to inform future strategies to manage at-risk pregnancies. The broad research question was what is the relationship between inequality and stillbirth, how has this been studied and with what effects?
We conducted a systematic review using the meta-narrative method,16–18 in accordance with the Realist And MEta-narrative Evidence Syntheses: Evolving Standards (RAMESES) standards.19 A RAMESES checklist is provided (online supplementary file 1).20 Our protocol21 (online supplementary file 2) specified four objectives:
To review the current body of knowledge of the relationship between inequalities and stillbirth across the natural and the social sciences.
To provide new insights into the interplay of biological, clinical, cultural and socioeconomic factors in increased stillbirth risk.
To explore the impact of interventions on inequalities.
To provide a narrative summary of this research for stakeholders tasked with reducing preventable stillbirth.
Meta-narrative review is a type of systematic review that was developed by Greenhalgh et al.16–18 Meta-narrative is a term for the unfolding storyline of research in a particular tradition or topic, which draws on the theoretical approach in Kuhn’s writing on paradigms.22 We used this approach to make sense of evidence from heterogeneous sources in which stillbirth and inequality have been variously conceptualised and studied over time. The method is underpinned by the methodological principles of pragmatism, pluralism, historicity, contestation, reflexivity and peer review. As a method, meta-narrative review involves six key stages17:
Planning: We registered our protocol with PROSPERO21 and assembled a multidisciplinary research team.
Iterative scoping searches and systematic electronic searches: Initial searches were designed to map the diversity of perspectives and approaches. We contacted experts in the field of stillbirth research and from disciplines contributing to inequalities research. Exploratory searches were conducted using the search term ‘stillbirth’ in 13 databases in health and the humanities (online supplementary file 3). Systematic searches were conducted in November 2017 in MEDLINE, Embase, CINAHL, PsycINFO, Popline, Historical abstracts, Humanities International Complete, Race Relations Abstract and SocINDEX (see online supplementary file 4: example systematic search strategy). An English language restriction was imposed, but no geographical or date restrictions. In our protocol, inclusion criteria were any study design (quantitative, qualitative or mixed methods) investigating stillbirth and inequality, in a high-income, middle-income or low-income setting. Following initial screening of titles and abstracts a pragmatic decision was made by the team to include only studies with a UK component. Unchanged exclusion criteria from the protocol were: any study in non-English language; of pregnancy loss <20 weeks gestation; of perinatal loss in the neonatal period; only involving participants who had assisted conception. The decision to exclude studies involving participants who had assisted conception was based on evidence of increased risk of stillbirth in pregnancies following In vitro fertilisation/Intracytoplasmic sperminjection (IVF/ICSI). We applied these criteria during the database searches where it was possible to exclude studies focusing specifically on assisted conception. Screening was independently undertaken by three authors (NC, KWF and CK), who also assigned potential inclusions to disciplinary categories at this stage (see online supplementary file 5: screening tool).
Mapping: A data extraction form was developed based on one used in earlier reviews,23 which was adapted for the purpose of this metanarrative review. Additional fields were added to capture data relating to how inequalities and stillbirth were conceptualised, defined and theorised. The form was piloted by extracting data from a subset of five papers (taken from across the research traditions) to test for applicability to the metanarrative, and refined. Extracted data were then summarised, tabulated and presented. During this phase, the team had lengthy discussions about which traditions were represented, the overlap between them and their distinctiveness. We classified traditions based on the distinctiveness of their lens (or in other words—paradigm). This involved consideration of scope, historical roots, key concepts, assumptions, theoretical basis, kinds of research questions asked and the methods used.
Appraisal: We stated in our protocol that all articles that met the inclusion criteria would be independently assessed by three researchers to minimise bias. During the process of the review, it became apparent that quality appraisal of all quantitative studies using the appropriate checklists from the Critical Appraisal Skills Programme (CASP) toolkit was not appropriate, with quality more suitably judged by the prevailing standards in each tradition. That said it was fitting to use CASP tools24 for some studies in the epidemiological tradition and the Walsh and Downe tool for qualitative research quality appraisal.25
Synthesis phase: The identification of the meta-themes was via a two-part synthesis: (1) at the level of the traditions, which unfolded in the mapping phase and (2) at the level of data extraction from primary studies across traditions. Part 1 involved evaluating the meta-narratives to identify and compare how the different research traditions conceptualised and theorised the topic, and the methodological approaches and study designs used. Differences in findings between the resulting meta-narratives were analysed interpretively to produce further insights. Part 2 of the synthesis process involved paradigm bridging (seeking commonalities in underlying conceptual and theoretical assumptions), paradigm bracketing (highlighting differences in these assumptions), interplay (exploring tensions) and meta-theorising (exploring patterns that span conflicting understandings) to construct summary meta-themes. KWF, NC and CK undertook the initial analysis and synthesis processes, with input from DR, MAT, CS and SD.
Recommendations phase: We engaged with local clinical networks and the national Stillbirth and Neonatal Death Charity to formulate recommendations.
Patient and public involvement
Author CS is a parent and vice-chair of the International Stillbirth Alliance and was involved in the design, and conduct of the review and the writing of this paper.
From electronic searches of nine databases, a total of 13 610 records were identified. Following duplicate removal 4934 records were screened (figure 1). We included 54 sources from nine research traditions spanning the period 1945–2017.26–78 Table 1 provides a summary of included research traditions. Chronologically, these traditions were Social Medicine26–31; Epidemiology32–48; Medical Sociology49–53; Public Health54–58; Spatial Epidemiology59–64; Social Psychology65; Audits, Reports and Confidential Enquiries66–74; Fetal-Maternal Medicine75–78 and Nursing and Midwifery (Garcia, Perinatal mortality in Pakistani, Bangladeshi and White British mothers in Luton). Online supplementary file 6 provides details about the characteristics of included sources. With the exception of epidemiology (n=17), most traditions generated few relevant papers. All research traditions used epidemiological data. We included one mixed-method study reporting qualitative data. No intervention studies were identified. Lack of studies, heterogeneity of study design, definitions of stillbirth and measurement of inequalities between studies, traditions and over time meant meta-analysis were not practical. Figure 2 maps the traditions contribution over time and the declining national stillbirth rate.
Synthesis within traditions
Table 1 summarises the unfolding storylines by research tradition and their conceptualisation of inequalities.
Synthesis across traditions
Meta-theme 1: something must be done
Across time and research tradition, the prevailing message was for action on inequalities and stillbirth. From the earliest included paper in Social Medicine that concludes ‘there is still much to be done’26 to a Public Health paper in The Lancet Ending Preventable Stillbirth Series 2016 that states ‘programmes at community and country-level need to improve health in disadvantaged families to address these inequalities’58 the message is clear. The call to do something stems from persistent evidence of a social gradient coupled with perceptions of insufficient progress in diminishing stillbirth rates in the UK. In some research traditions, stillbirth was used as an indicator of societal health, with references to the particularly low stillbirth rates achieved in Scandinavia commonplace. Despite the persistence of studies reporting the same or similar risk factors and the continuation of the social gradient exactly what kind of ‘something should be done’ is less clear. Evidence of effectiveness was absent for interventions at specific time points, intergenerationally, at scale or targeted to social groups. The absence of stillbirths in inequalities reduction targets post-Acheson was identified as a specific barrier to action.71
Meta-theme 2: problems of precision
Our meta-narrative approach highlighted how much of the challenge in seeking to act on inequalities and stillbirth lies in the lack of consensus and inherent complexities inherent to both. While there was persistent evidence of associations between stillbirth risk and poverty, and stillbirth risk, ethnicity and poverty, it was not possible to estimate the potential gain on stillbirth reduction if action was taken to reduce inequalities, because of problems with data availability and comparability. There were problems of precision in stillbirth definition and problems of precision in inequalities measurement.
The traditions rooted in medical science offered the most analytic tools for defining when stillbirths happened (antepartum and intrapartum), at what gestation (early preterm, late preterm and term), and why in terms of clinical factors (classification according to ReCoDe, Wigglesworth, Aberdeen, etc), but these definitions were not used consistently, and they rarely considered social inequalities as underlying factors.
Further problems of precision arose from how inequalities were variously conceived and measured, even when they were taken into account. In traditions informed by the social sciences, inequalities were broadly conceptualised as a set of social relations (rather than a variable/s), which opened up lived experience, multiple risk factors/interactions between them, and consideration of the relationship between structure and agency in health and lifestyle. Further conceptual considerations arise from this, including socioeconomic status/social class (an individual measure of inequality) based on occupation alone or in combination with income, education and culture (Social Medicine, Epidemiology, Medical Sociology and Public Health). The problem of how best to measure disadvantage was apparent across time. The artefact explanation for inequalities (which considers to what extent they are a construct of the measurement process) was particularly critical of the now defunct Registrar General’s Scale.31 50 51 54 55
Deprivation (an area measure of inequality) was conceptualised according to the tool used to define it for which there was no consensus. Tools used included the Townsend deprivation index, Carstairs and Morris index, Jarman Deprivation Scores and the Index of Multiple Deprivation (IMD). A general question for the spatial epidemiology tradition was whether individual-level deprivation and area deprivation are different and how they interact.61 62 The problems associated with using crude categories to define ethnicity (ie, white, black, Asian) were also considered (Epidemiology, Medical Sociology and Public Health) and the complexities therein (ie, benefits of more subtle classifications incorporating country of birth such as British Asian), including how such classifications are only proximate guides to experiences, practices, beliefs and lifestyles. In 1993, a matrix of country of birth, nationality, language group, religious affiliation and (where appropriate) region, caste and subcaste was proposed by Andrews and Jewson to test the combining variables, as well as suggesting a more fine-grain exploration of major variables if used as part of a national dataset.52
Meta-theme 3: moving from associations to intersectionality and intervention
All the traditions included in this review report evidence of associations between living in poverty and increased risk of stillbirth. However, despite more than 70 years of research equating inequality with increased stillbirth risk ‘any detailed study of why this should be so is surprisingly sparse’. (Macintyre, p.393)50 This theme attempts to shine some ‘light on the most appropriate times to provide support and the form(s) that such support should take.’ (Weightman, p11)42 To begin to address the need for intervention, one recent study triangulated epidemiological data with what women said (qualitative data) (Garcia, Perinatal mortality in Pakistani, Bangladeshi and White British mothers in Luton). In so doing, it showed how the interactions between education level, socioeconomic status, cultural needs, language barriers, knowledge, likeliness to seek help and assumptions by healthcare staff interact to make (or diminish) stillbirth risk in the current maternity care system. While that study was the first study to claim an intersectionality approach, most publications across the research traditions suggest that further exploration of the interactions between risk factors, and within specific groups, is warranted.
Most of the contributory risk factors identified in this review are already well known and have been for some time. As summarised in figure 3, risk factors for stillbirth encompass biological, clinical, behavioural, health service and social factors. Figure 3 provides a model from which to test the associations between factors, which is built on interdisciplinary evidence of the clinical causes of stillbirth, theories of natural and social selection, cultural/behavioural/lifestyle explanations, area effects, materialist/structuralist explanations and availability, access and quality of care. While some studies proposed antenatal screening for a combination of social factors (ie, non-English speaking, unemployed household) in combination with behavioural factors (ie, smoking) and clinical factors (ie, previous intrauterine growth retardation), there was little consensus on specific factors, timing, or outcome if social conditions remain the same.39 40 46
This review highlights that research investigating what might work to reduce inequalities and stillbirth in the UK is underdeveloped. We identified nine research traditions in the field but, with the exception of epidemiology, these traditions had few studies within them. Across all traditions, epidemiological data persistently suggest that membership of a lower socioeconomic group (as measured by an individual’s occupation) or residing in a disadvantaged community (as measured by local area deprivation) is associated with increased incidence of stillbirth when compared with more socially advantaged counterparts. However, there was a paucity of research investigating why this should be so, despite repeated calls for action. A few studies found no association between living in an area of deprivation and increased stillbirth risk. Why this was so is also unclear. This review shows that the field is complex, and dynamic, with the respective components (stillbirth per se and inequalities per se) beset by conceptual and methodological challenges. In terms of advancing understanding about the complexity of the interactions between factors associated with increased stillbirth risk, this review is limited. Moreover, we found no studies of interventions targeted to reduce stillbirth in specific social groups or communities. Nonetheless, what this review does add is that stillbirth is a useful marker of success in addressing inequalities. It provides a cross-disciplinary foundation from which to develop and stimulate hypotheses about the relative influence of biological, clinical, behavioural, health service and social factors on birth outcomes and the interactions between these various determinants to inform future interventions.
Strengths and limitations
This study used a meta-narrative approach to investigate the association between inequalities and stillbirth. We adhered to the RAMESES standards for meta-narrative review to ensure fidelity with the methodology. We used a multipronged approach to retrieving sources that included exploratory searches, systematic searches, hand searches, expert opinion and forward and back chaining, which gave us a broad capture of relevant documents. By limiting the review to UK-based studies only, we were able to focus with greater acuity on the commonalities and contestations between research traditions. However, excluding studies from other countries may have led us to miss important research on the association between stillbirth and inequalities of relevance both in the UK context and globally. The quality of some of the included sources in this review may also be considered an important limitation with the use of prespecified quality appraisal tools24 25 not deemed appropriate for all traditions.
The interpretive nature of meta-narrative review means another team, outside of the UK, may classify the traditions differently. If, for example, Social Medicine and Medical Sociology were grouped together, this would change the number and chronology of included traditions, although the interpretive synthesis across traditions is likely to remain intact.
Relationship of findings to other research
The current abundance of research investigating stillbirth prevention and bereavement care in the UK is a recent development as efforts to break the silence that has traditionally surrounded stillbirth have gained momentum and international ambition to reduce stillbirth has intensified over the last decade.3 4 6 79–82 This goes some way to explain why the field is underdeveloped in comparison to the wider health inequalities literature on mortality and social gradient. We were surprised to find no intervention studies, although there is an acknowledged paucity of evaluations of interventions to reduce inequalities in health in general.83–86 In the international literature, public health interventions seeking to reduce stillbirth are also sparse. The few that do exist include a food supplementation programme, which was offered to low-income women in the USA,87 and a study looking at household air pollution in India, where wood and kerosene cooking fuel, more commonly used in low-income households, is known to be associated with stillbirth.88 However, neither of these address the underlying structural components of disadvantage.
Implications for clinicians and policy-makers
This review suggests that addressing inequalities as a component of stillbirth prevention in the UK demands intervention at many levels. The paucity of directly relevant research to the question of stillbirth prevention means policy-makers must look towards what works to reduce inequalities for other related causes of death (ie, sudden infant death, cardiovascular disease and cancer). Health inequalities theory advocates intervening at specific time points during the life course (ie, pregnancy and the early years), interventions that have impact over time (ie, intragenerational and intergenerational), interventions at scale (ie, national policies) and interventions targeting specific groups (ie, ethnic minorities and lower social classes). Addressing nutrition, service uptake and the wider social determinants of health may have knock on effects on many clinical outcomes, including stillbirth.89 Scotland’s Early Years Collaborative that encompasses cross-sector interventions at the level of individuals, groups, organisations and society, includes a specific stillbirth reduction target.86 In the absence of a hierarchy of causation among these complex effects, stillbirth-specific research is well justified, as long as it is embedded in implementation, public health and caring for and about people.
In the global health community, remediable differences between and within countries are increasingly being addressed by agendas for health equity.1 89 The equity in health agenda is distinct in its focus on unnecessary and avoidable differences in health that are considered unfair and unjust. However, in the UK, inequality is a term that has endured.13 14 86 90 Future research in the field of inequalities and stillbirth would benefit from a more precise definition of the term inequalities that takes into account the concurrent global agenda for equity in health.
Unanswered questions and future research
It was not possible within or across traditions in this review to determine the potential gain of inequalities and stillbirth reduction. The field would benefit from a national consensus for routinely collected data and future research at population level. MBRRACE-UK, the Royal College of Obstetricians and Gynaecologists (RCOG) and National Health Service England now have a high level of precision in stillbirth definition and national data capture. Since 2014, MBRRACE-UK has consistently used the Children in Low-income Families Local Measure.5 There is also a simultaneous need for qualitative research that gets behind classificatory system labels to the lived realities of groups and communities. This review highlights there have long been important differences between communities and place that, for example, the classification Black, Asian and Minority Ethnic or IMD can conceal. Most of the factors associated with inequalities and stillbirth identified in this review are already well known, and have been for some time. The findings of the review suggest that looking at these well-known factors afresh is likely to provide new insights. For example, the reasons reported as to why women delayed seeking care for reduced fetal movements in this review resonate with the findings of earlier reviews of antenatal care in general.91 92 Similarly, studies of smoking behaviours, influence of social and community networks, the conditions in which people live and the impact of current UK smoke-free policies that were identified on the periphery of studies included in this review, demand cross-disciplinary consideration in future strategies for stillbirth prevention.93–95 Not least because, these particular components of antenatal care already feature as part of stillbirth reduction initiatives, but to date, have had limited success.82
The role of social factors, modifiable lifestyle behaviours and antenatal interventions in stillbirth prevention are current research priorities identified by the stillbirth community.96 The results of this review indicate that there is little effective work across disciplines despite the long-recognised need for it. We recommend that the UK stillbirth research community overcome this by setting up a dedicated forum to promote intervention and implementation research in this area. The forum could have three roles: (1) define the framework for future research by identifying the ways in which disciplines should interact; (2) develop data standards for information relating to stillbirth and inequalities and (3) develop and promote the intervention and implementation research, policy and practice agenda relating to stillbirth and inequality.
The UK government’s current ambition is to halve the national stillbirth rate by 2025. Research investigating and, critically, addressing inequalities and stillbirth in the UK is underdeveloped. This is despite repeated evidence of an association between stillbirth risk and poverty, and stillbirth risk, poverty and ethnicity. A specific research forum is required to lead the development of research and policy, which can harness multiple relevant research perspectives and address the intersections between different policy areas. This review not only unifies calls for action, by connecting multidisciplinary insight into these complexities, challenges and opportunities, it provides a starting point for a novel transdisciplinary response.
Rob Rawcliffe, UCLanPrint for his design input into figure 3.
Contributors CK, DR, MAT and CS designed the review with input from SD. NC and KWF conducted the searches, identification and screening with agreement by consensus of all authors on final inclusions. NC, KWF and CK extracted data, and agreed initial storylines and final meta-themes with review by SD, DR, MAT and CS. CK wrote the first draft of the paper. All authors read, commented and approved the final manuscript.
Funding This study was supported by Stillborn and Neonatal Death Charity (RF510).
Competing interests CK, SD, NC, KWF and CS report a grant from SANDS, the Stillbirth and Neonatal Death Charity, during the conduct of the study. CS also reports her position as vicechair of the International Stillbirth Alliance (ISA). DR and MAT have nothing to disclose.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.