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Research

Maternal and fetal risk factors for stillbirth: population based study

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f108 (Published 24 January 2013) Cite this as: BMJ 2013;346:f108
  1. Jason Gardosi, director1, professor of maternal and perinatal health2,
  2. Vichithranie Madurasinghe, epidemiologist1,
  3. Mandy Williams, research midwife1,
  4. Asad Malik, data analyst1,
  5. André Francis, statistician1
  1. 1West Midlands Perinatal Institute, Birmingham B6 5RQ, UK
  2. 2University of Warwick Medical School, Coventry CV4 7AL, UK
  1. Correspondence to: J Gardosi jason.gardosi{at}pi.nhs.uk
  • Accepted 18 December 2012

Abstract

Objective To assess the main risk factors associated with stillbirth in a multiethnic English maternity population.

Design Cohort study.

Setting National Health Service region in England.

Population 92 218 normally formed singletons including 389 stillbirths from 24 weeks of gestation, delivered during 2009-11.

Main outcome measure Risk of stillbirth.

Results Multivariable analysis identified a significant risk of stillbirth for parity (para 0 and para ≥3), ethnicity (African, African-Caribbean, Indian, and Pakistani), maternal obesity (body mass index ≥30), smoking, pre-existing diabetes, and history of mental health problems, antepartum haemorrhage, and fetal growth restriction (birth weight below 10th customised birthweight centile). As potentially modifiable risk factors, maternal obesity, smoking in pregnancy, and fetal growth restriction together accounted for 56.1% of the stillbirths. Presence of fetal growth restriction constituted the highest risk, and this applied to pregnancies where mothers did not smoke (adjusted relative risk 7.8, 95% confidence interval 6.6 to 10.9), did smoke (5.7, 3.6 to 10.9), and were exposed to passive smoke only (10.0, 6.6 to 15.8). Fetal growth restriction also had the largest population attributable risk for stillbirth and was fivefold greater if it was not detected antenatally than when it was (32.0% v 6.2%). In total, 195 of the 389 stillbirths in this cohort had fetal growth restriction, but in 160 (82%) it had not been detected antenatally. Antenatal recognition of fetal growth restriction resulted in delivery 10 days earlier than when it was not detected: median 270 (interquartile range 261-279) days v 280 (interquartile range 273-287) days. The overall stillbirth rate (per 1000 births) was 4.2, but only 2.4 in pregnancies without fetal growth restriction, increasing to 9.7 with antenatally detected fetal growth restriction and 19.8 when it was not detected.

Conclusion Most normally formed singleton stillbirths are potentially avoidable. The single largest risk factor is unrecognised fetal growth restriction, and preventive strategies need to focus on improving antenatal detection.

Footnotes

  • We thank our regional network of bereavement midwives who submit notifications on all perinatal deaths; Ann Tonks, Catherine Franklin, and Robyn Caley who run the regional perinatal mortality registers for ensuring high quality ascertainment; the network of unit based data clerks who enter the regional maternity dataset for each pregnancy on the PEER electronic record (www.pi.nhs.uk/peer); and Michelle Southam and Lorraine Ecclestone for ensuring data quality through a rolling programme of training and accuracy audits.

  • Contributors: All authors had full access to the data, assisted with its analysis and interpretation of the results, and reviewed and approved the final manuscript. JG developed the study design, assisted with the analysis and interpretation, and wrote the paper. He has final responsibility to submit for publication, and is the guarantor.

  • Funding: Data collection and analytical staff were financially supported by NHS West Midlands Strategic Health Authority and all primary care trusts. The funders had no influence on the study design, analysis, interpretation, writing up of the manuscript, or the decision to submit for publication.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, and no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not required; data were collected with patient consent and were pseudonymised before analysis.

  • Data sharing: No additional data available.

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