Systematic review of placental pathology reported in association with stillbirth

Abstract

Introduction: Histopathological examination of the placenta is recommended to determine the cause of stillbirth. Although some reports find causal or contributory placental abnormalities in up to 60% of stillbirths, the significance of such findings in this clinical setting remains uncertain. A systematic review was conducted to i) investigate the likelihood of diagnosing a cause of stillbirth from placental examination and ii) to identify the specific causes of death that can be diagnosed from placental pathology.

Methods: Medline, Embase, Biosis, and Web of Science were searched using the terms "stillbirth", "histopathology", "pathology", and "placenta". Case-reports, narrative review articles and studies that failed to define diagnostic sub-groups were excluded. 473 potential studies were identified. Relevant studies (n = 41) were subdivided into those that investigated causes of stillbirth (n = 13), and those that identified conditions associated with stillbirth (n = 5). The contributory value of placental examination to stillbirth classification was evaluated in 10 studies and the role of specific placental abnormalities in the aetiology of stillbirth in 20 studies.

Results: The proportion of stillbirths attributed to a placental cause ranged from 11 to 65%. Classification systems which included multiple placental categories and allowed placental findings to supersede other disorders reported higher rates of placental causes and fewer unexplained stillbirths. Diagnoses were frequently based on qualitative, non-specific terminology.

Conclusions: The utility of histopathological examination of the placenta is affected by the classification system used. International consensus is required for both diagnostic criteria and terminology to describe placental abnormalities and on classification of stillbirths..

Keywords: Perinatal death; Placental histopathology; Stillbirth.