Summary of included research traditions
| Research tradition | Academic discipline | Definition and scope | Unfolding storyline | Inequalities conceptualised as | Included references |
| Social medicine | Medicine | Social medicine is a branch of medicine that uses epidemiological methods to establish a problem exists, determining factors and opportunities for preventative action. The tradition is distinctive in its thought on the interconnectedness between biological factors (ie, mother’s age) that have meaning whatever the social context and social factors (ie, occupational social class) that derive their meaning from social organisation in human life emulating political economy concerns. | The social medicine26–31 storyline begins with the investigation of how social and economic factors influenced the decline in stillbirths and early neonatal deaths in Scotland, England and Wales, between 1939 and 1944. Baird26 attributed this fall to the improved nutrition of the mothers during pregnancy, a consequence of the national distribution and consumption of milk and other foods important for health during the second world war. These improvements affected every area, age group and parity. By 1949, the decline in the stillbirth rate had slowed, despite the introduction of the National Health Service. Four papers, from a series in The Lancet in 195527–30 sought to understand why. The last paper concluded the independent effects of social class, region, the mother’s age and parity on stillbirth risk. Illsley31 showed how occupational class may be more than a measure of inequality simply based on environmental conditions at the time of maternity, reporting that it can also be a marker of a woman’s personal characteristics (height, physique, health, intelligence and nutrition), education and social habits. Women who were intergenerationally upwardly socially mobile at marriage experienced fewer stillbirths. | A variety of social factors that combine with biological characteristics to increase vulnerability to stillbirth risk. | n=6 (26–31) |
| Epidemiology | Medicine | Epidemiology, developed out of the biomedical model as a specific line of inquiry. Initially epidemiology focused exclusively on epidemics of communicable diseases but subsequently expanded to address endemic communicable diseases and non-communicable infectious diseases. It is the study of the distribution and determinants of health-related states (especially disease), and the application of findings to the control of diseases and other health problems. | The epidemiology 32–48 storyline is characterised by its increasingly sophisticated use of data and the repetition of the same or similar findings over time. Of the 17 studies aligned to this tradition, six were landmark papers, repeatedly referenced within the field.32–37 Although most authors highlighted a significant decrease in UK stillbirth rates since the 1960s, studies repeatedly showed that the social gradient remained constant.36 37 41 Within overall stillbirth rates, being in a lower socioeconomic class (as measured by an individual occupation) or residing in a disadvantaged community (as measured by local area deprivation), were relatively consistent markers of increased incidence of stillbirth, when compared with more socially advantaged counterparts. An important strength is epidemiology’s identification of clinical, socioeconomic and lifestyle factors associated with an increased risk of stillbirth across relatively large populations. Early studies used the Registrar General’s Scale of occupational social class as a measure of inequality; later studies use the socioeconomic classification scheme. Other studies still used the term ‘deprivation’ to signify inequality. In most of the studies, using deprivation as a factor the risk of stillbirth increases with increasing levels of deprivation34 43 44 although this is not always the case.38 Epidemiological studies looking at ethnicity as a measure of inequality are a relatively recent phenomenon and do not show the same level of consistency, although the rates of stillbirth for women of African-Caribbean origin remain at twice the rate of white women.38 45 Studies exploring the stillbirth rates of women of Asian origin show a degree of variance with some authors highlighting an increased rate—equivalent to women of African-Caribbean origin38; while other studies indicate a much lower rate—similar to Caucasian women.45 | A variety of factors (social class, living in an area of deprivation, occupation of partner, ethnicity, etc.) associated with an increased relative risk of stillbirth. | n=17 (32–48) |
| Medical sociology | Sociology | Medical sociology is the study of the social causes and consequences of health and illness. This tradition has positivist and interpretative, theoretical and empirical, quantitative, qualitative, and mixed-methods and cross-disciplinary branches. The persistence of social class gradients despite the demographic and epidemiological changes associated with the transition to modernity was an important focus during the 1970s and 1980s. During the 1990s, research increasingly focused on lay understandings of health and illness and lived realities. | The medical sociology49–53 storyline is theoretical. Early sociological explanations for the persistence of the social gradient in stillbirth encompassed theories of capital assets (the physique, stature, nutrition of the mother), social mobility (a direct thread from social medicine31, and time lag (whereby developments in healthcare take time to reach those most in need, benefiting those better off first).49 After the seminal Black report54 more nuanced considerations of gender, age, ethnicity and area of residence, alongside occupational class, as simultaneous and overlapping vulnerabilities, were developed.50–52 These encompassed the broad consideration of life circumstances, behaviours and beliefs/attitudes50 and the precise disaggregation of the concept of ‘deprivation’ to reveal the complexity of materialist risks (and protections against those risks), which helps to explain the ambiguous association between economic deprivation and ethnicity.52 | A set of social relations (rather than just a variable), which opens lived experience and multiplicity of factors at play (ie, poverty, poor housing, nutrition, welfare) and relationship between structure and agency. | n=5 (49–53) |
| Public health | Public health | Public health is concerned with preventing disease, prolonging life and promoting health through organised efforts of society. From 18th and 19th century roots, during the 1980s, there was a revival of public health policy. In the UK, this coincided with a shift in thinking that morbidity or general health status had become the more important indicators of inequality, and increasing interest in individual behaviours and lifestyle as determinants of health. | The public health storyline54–58 unites the seminal Black report54 (which had a major impact on research into inequalities in health in the UK), with seminal papers from the two Lancet Stillbirth Series57 58 that were of equal significance to the stillbirth research and policy community. In the former publication54, stillbirth is a crude cause of death category, used as part of efforts to explain general trends in inequalities in health, based principally on measures of occupational social class from which artefact, natural selection, structuralist and behaviourist explanations, (alongside the need to build on the idea of multiple causation) were developed. In the latter publications, distinguishing between different kinds of stillbirth and the importance of making each stillbirth count, come alongside the need to build on the idea of interactions between factors that include social disadvantage.57 58 The lack of targeted interventions for black and ethnic minority women in the UK, despite their complex patterns of increased risk and known underutilisation of maternity services, was highlighted in the scoping review by Garcia et al.56 In 2016, there was an explicit recall to action to tackle inequalities and stillbirth within HICs by addressing structural factors (such as poor housing, poverty) and factors, which limit women's access to antenatal care.58 | An additional risk and considered in relation to providing targeted care to populations considered at risk. | n=5 (54–58) |
| Spatial epidemiology | Medical geography and epidemiology | Spatial epidemiology is concerned with the spatial analysis of disease incidence and prevalence. It uses geographical mapping and statistical modelling to understand the spatial distribution of disease, under the assumption that this will provide indications of the environmental contributors to the disease. | The spatial epidemiology59–64 storyline begins in the late 1980s and attempts to address how community deprivation and individual social class might each contribute to risk of stillbirth. Studies looking at stillbirth and inequalities have investigated the relative importance of individual level (Registrar General Social Class) versus area level (eg, Townsend Score) measures of inequality. Studies report contradictory findings, perhaps revealing the complexity of how individual (compositional) and area (context) effects interact to affect risk, with some reporting an enduring association between area and/or individual level deprivation and stillbirth risk59 61–63 and others reporting no association60 64. The storyline of UK-based research into place effects on stillbirth risk has so far conceptualised geographical areas as ‘containers’ of people, rather than seeing place as socially constructed. | A variety of factors (social class, living in an area of deprivation, occupation of partner, ethnicity) associated with an increased relative risk of stillbirth. | n=6 (59–64) |
| Social psychology | Psychology | Social psychology is the study of human social behaviour, emotion and cognition. With its focus on both the individual and society, it draws on sociological and psychological perspectives Research methods involve both quantitative and qualitative approaches, and include surveys, participant observation, laboratory experiments, field experiments, and archival and content analyses. Experimental social psychology is underpinned by positivist assumptions, while other approaches such as critical social psychology, operate from a social constructionist stance. | The social psychology65 storyline arose from the Black report54 and draws on theoretical explanations from the black report about the association between social inequality and ill health. This storyline is represented by one paper from 199065, which used secondary data (birth data from England Wales, 1980–1986) to develop a theoretical model of how social class may affect psychosocial mediators—emotional, social and cognitive factors—which may in turn influence pregnancy outcome, either directly or mediated through behaviours and coping strategies. The proposed model suggests that material deprivation results in more negative life events while also reducing social support, and access to education and information. Stressful life events, unmitigated by social support, create stress, anxiety, depression, low self-esteem. Poor education or access to information leads to a lack of knowledge and to deleterious beliefs and attitudes. The combined emotional and cognitive effects produce coping strategies and behaviours that increase the risk of negative pregnancy outcomes (ie, smoking).65 | A factor influencing health Inequalities can be seen to affect health via increasing psychosocial stress, which can then directly impact on health and also induce health-limiting behaviours. | n=1 (65) |
| Audit reports and confidential enquiries | Interdisciplinary (epidemiology, obstetrics, paediatrics, midwifery) | Audits, reports and confidential enquiries provide knowledge not always thought of as research, nevertheless it usefully uses routinely collected data to examine time trends. As a tradition, it incorporates a variety of approaches including epidemiology, economics and health policy and may be further informed by qualitative data and/or expert opinion. It includes 1992–2003 Confidential Enquiry into Stillbirths and Deaths in Infancy, 2003–2011 Centre for Maternal and Child Enquiries and 2011 onwards MBRACE-UK (Mother and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK). | The audit, reports and confidential enquiries storyline66–74 builds on over 50 years of local and national reporting of maternal and infant deaths. A key feature of these reports is the presentation of stillbirth rates at national, regional and local levels and the subsequent comparisons between geographical units and benchmark averages. Over the years, these processes were modified and refined into the national Confidential Enquiry scheme66 67and, more recently, under the banner MBRACE-UK 68–70. Although we identified more than 20 national reports, only five explored the association between inequalities and stillbirth66–70 with the majority focusing on ‘avoidable’ health system and clinical failures. Where inequalities and stillbirth were identified they were discussed in relation to lifestyle factors (smoking, excess alcohol consumption, obesity) or regional or ethnic disparities associated with increased stillbirth risk. Four regional reports or audits from the West Midlands71–74 attempt to look at stillbirth and inequalities explicitly by equating higher indices of Multiple Deprivation Index (IMD) with increased stillbirth rates. These reports were more nuanced and identify a number of social and medical risk factors that could be screened for (alone or in combination) to predict risk of stillbirth (eg, unemployment, inappropriate housing, unsupported/difficult family circumstances, emotional factors/anxiety, maternal age <20 years or >40 years, obesity, smoking, consanguinity, history of mental health issues). The authors of these reports also highlight fetal growth restriction as a potential predictor of stillbirth in deprived communities. | Regional variations in stillbirth rates with recognition of differences between areas of deprivation (high and low) and ethnicity (white and black and Asian populations). | n=9 (66–74) |
| Fetal–maternal medicine | Medicine | Maternal–fetal medicine is a subspecialty of obstetrics. Its focus is on ‘high-risk’ pregnancies, including women who have a pre-existing illness or a pregnancy-induced illness and congenital abnormalities. It draws on and is related to perinatal epidemiology. The clinical focus includes preterm birth prevention, screening for fetal growth restriction and placental histopathology. | The fetal–maternal medicine storyline75–78 included a study reporting that women living in areas of highest deprivation (IMD 1) were more likely to experience fetal growth restriction compared with women living in the least (IMD 3–9).75 Approximately 46% of these women smoked, compared with 7% in the least deprived. The study concluded that targeted antenatal management was key to stillbirth prevention among women living in the most deprived areas. This tradition also offered three interlinked publications, which suggested that maternal ethnicity was associated with fetal loss at different gestations White women had relatively more stillbirths (>24 weeks gestation) and black women relatively more late intrauterine fetal deaths (20–23 weeks gestation)76–78. There was a higher risk of ascending genital infection for black mothers relative to women from other ethnic groups. This was a relatively common cause for early intrauterine fetal death, peaking at around 22 weeks.78. | A risk factor for stillbirth and depending on the type of study, may be included as a covariate in the analysis. | n=4 (75–78) |
| Nursing and midwifery | Nursing and midwifery | Nursing and midwifery research draws from positivist and interpretative paradigms, using a range of quantitative and qualitative methods. This tradition has made a significant contribution to the body of knowledge about stillbirth and bereavement care. | Only one mixed-method single-site study was identified as characteristic of this tradition (Garcia, perinatal mortality in Pakistani, Bangladeshi and white British mothers in Luton). It showed no statistically significant association between stillbirth and maternal ethnicity, but found more perinatal deaths in deprived areas. Qualitative interviews with White British, Pakistani and Bangladeshi women identified health beliefs and behaviours common to all ethnic groups. These included little awareness of what to do about risk factors such as reduced fetal movements (‘2 days I delayed because I don't know what I need to do’) and anxieties about being a burden to overstretched maternity services (‘they could do without me taking up a bed, taking up their time…, you put yourself at a lower scale than everyone else.’) Health professionals perceived they had communicated information to women about stillbirth risks and the importance of seeking prompt care. Professionals did not view any particular ethnic group to be higher risk, but were aware of how cultural norms and/or living in poverty can restrict access to timely care (‘Some of them(Asian women: Pakistani and Bangladeshi)are beholden on their partners to get them there) (‘It doesn’t matter whether they’re Asian or whatever they are… They don’t have transport and they don’t have money, they don’t have access to actually get here’). | An additional vulnerability, and considered in relation to the importance of providing culturally appropriate care. | n=1 (Garcia, perinatal mortality in Pakistani, Bangladeshi and white British mothers in Luton). |
HIC, high-income country.