Study characteristics
Of 791 studies identified in our search, 15 met inclusion and exclusion
criteria and were included for analysis (Figure
1 ).17-32 Five studies were excluded as they either
did not provide data in an extractable format or used language spoken at
home or country of birth as a surrogate for
ethnicity.33-37 Characteristics of the included
studies are presented in Table S1 . These fifteen studies
encompassed 72,555 stillbirths, equating to a stillbirth rate ranging
from 0.35% to 6.8% of all births. Seven were conducted in the United
States of America, five in Australia, and three in the United Kingdom.
Most (n = 10) were conducted more than 10 years ago and of these,
six had data collected more than 20 years ago. Three studies were
limited to a single institution, seven were multicentred, and five were
conducted at a population or national level. Only eight of the included
studies provided an indication of the autopsy rate. In these studies,
the autopsy rate ranged from 37.6% to 100%. While the definition of
stillbirth varied slightly between studies, a majority of studies
defined stillbirth as death of foetus of at least 20 weeks’ gestation.
The classification system used to describe the cause of stillbirth
varied widely, with four studies using the ICD system, three studies
using INCODE, two studies using PSANZ, and six using a classification
system unique to the study. Most studies were either retrospective
cohort studies (n = 7) or cross-sectional in nature (n =
4), three were case-control, and one was prospective. Only one study was
deemed to be of high quality; the rest were deemed to be either medium
(n = 7) or low (n = 7) quality (Table S2 ).