Socioeconomic inequalities in the rate of stillbirths by cause: a population-based study
- Sarah E Seaton1,
- David J Field1,
- Elizabeth S Draper1,
- Bradley N Manktelow1,
- Gordon C S Smith2,
- Anna Springett3,
- Lucy K Smith1
- 1Department of Health Sciences, University of Leicester, Leicester, UK
- 2Department of Obstetrics and Gynaecology, NIHR Biomedical Research Centre, University of Cambridge, Cambridge, UK
- 3Centre of Environmental and Preventive Medicine, Queen Mary, University of London, London, UK
- Correspondence to Sarah E Seaton; sarah.seaton{at}le.ac.uk
- Received 8 March 2012
- Accepted 30 April 2012
- Published 25 June 2012
Abstract
Objective To assess time trends in socioeconomic inequalities in overall and cause-specific stillbirth rates in England.
Design Population-based retrospective study.
Setting England.
Participants Stillbirths occurring among singleton infants born between 1 January 2000 and 31 December 2007.
Main outcome measure Cause-specific stillbirth rate per 10 000 births by deprivation tenth and year of birth. Deprivation measured using the UK index of multiple deprivation at Super Output Area level.
Methods Poisson regression models were used to estimate the relative deprivation gap (comparing the most and least deprived tenths) in rates of stillbirths (overall and cause-specific). Excess mortality was calculated by applying the rates seen in the least deprived tenth to the entire population at risk. Discussions with our local NHS multicentre ethics committee deemed that this analysis of national non-identifiable data did not require separate ethics approval.
Results There were 44 stillbirths per 10 000 births, with no evidence of a change in rates over time. Rates were twice as high in the most deprived tenth compared with the least (rate ratio (RR) 2.1, 95% CI 2.0 to 2.2) with no evidence of a change over time. There was a significant deprivation gap for all specific causes except mechanical events (RR 1.2, 95% CI 0.9 to 1.5). The widest gap was seen for stillbirths due to antepartum haemorrhages (RR 3.1, 95% CI 2.8 to 3.5). No evidence of a change in the rate of stillbirth or deprivation gap over time was seen for any specific cause.
Conclusion A wide deprivation gap exists in stillbirth rates for most causes and is not diminishing. Unexplained antepartum stillbirths accounted for 50% of the deprivation gap, and a better understanding of these stillbirths is necessary to reduce socioeconomic inequalities.
Footnotes
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To cite: Seaton SE, Field DJ, Draper ES, et al. Socioeconomic inequalities in the rate of stillbirths by cause: a population-based study. BMJ Open 2012;2:e001100. doi:10.1136/bmjopen-2012-001100
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Contributors SES undertook the statistical analysis and wrote the first draft of the paper. LKS, BNM, ESD and DJF made substantial contributions to conception and design. LKS, ESD and AS were responsible for acquisition of data. LKS made a substantial contribution to the statistical analysis. All authors contributed to interpretation of the data, writing of the paper and revising it critically for important intellectual content. All authors approved the final version of the paper. SES is the guarantor.
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Funding This study was supported by UK Department of Health's National Institute of Health Research (RP-PG-0407-10029).
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Competing interests None.
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Ethics approval This study is based on routinely available national data that are anonymised, and hence, there is no requirement for ethical approval. We have clarified this in the manuscript.
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Provenance and peer review Not commissioned; externally peer reviewed.
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Data sharing statement There are no additional data available.
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