Cause of and factors associated with stillbirth: a systematic review of classification systems.

Introduction

An estimated 2.6 million stillbirths occur worldwide each year. A standardised classification system setting out possible cause of death and contributing factors is useful to help obtain comparative data across different settings. We undertook a systematic review of stillbirth classification systems to highlight their strengths and weaknesses for practitioners and policymakers

Material and methods

We conducted a systematic search and review of the literature undertaken to identify classification systems used to aggregate information for stillbirth and perinatal deaths. Narrative synthesis used to compare range and depth of information required to apply the systems, the different categories provided cause of and factors contributing to stillbirth. Results: A total of 118 documents were screened; 31 classification systems were included, of which 6 were designed specifically for stillbirth, 14 for perinatal death, 3 systems include neonatal and 2 include infant deaths. The majority (27/31) were developed in and first tested using data obtained from high-income settings. All systems require information from clinical records. One-third of the classification systems (11/31) include information obtained from histology or autopsy. The percentage where cause of death remained unknown ranged from 0.39% using the Nordic-Baltic classification to 46.4% using the Keeling system.

Conclusion

Over time, classification systems have become more complex. The success of application is dependent on the availability of detailed clinical information and laboratory investigations. Systems which adopt a layered approach allow for classification of cause of death to a broad as well as to a more detailed level.