Stillbirths: results of a pilot population-based surveillance system in Italy (SPItOSS)

Objectives: to describe the results of a pilot population-based perinatal mortality surveillance system, with regards to stillbirths; to study maternal, obstetric, and foetal characteristics, evaluating risk factors and understanding causes.

Design: a cross-sectional study was conducted on incident cases of stillbirths collected by the surveillance system from July 2017 to June 2019 in three Italian Regions (Lombardy, Tuscany, and Sicily).

Setting and participants: data on stillbirths, resulting from the in-hospital multidisciplinary audits, organised using the Significant Event Audit methodology, were analysed. According to the World Health Organization (WHO) definitions, the project identified stillbirths as foetuses born dead >=28 weeks of gestation. The WHO International Classification of Diseases-Perinatal Mortality was used to categorise the causes of foetal death.

Main outcomes measures: maternal characteristics, obstetric and foetal findings were investigated. Unadjusted relative risks and 95% confidence intervals were computed with respect to the background population. Finally, causes of death and contributing maternal conditions have been considered.

Results: the maternity and neonatal units of the three participating Regions notified 520 stillbirths, of which 435 cases underwent to the multidisciplinary audit (83.7%); 40.0% of cases occurred in the gestational age range between 36 and 39 weeks. The risk of stillbirth was significantly increased in mothers with foreign citizenship (RR: 1.39; 95%CI: 1.13-1.71), multiple pregnancies (RR: 1.59; 95%CI 1.05-2.42), and pregnancies conceived with assisted reproductive technologies (RR: 2.15; 95%CI 1.45-3.19). The rate of congenital malformations was 6.0%. A diagnosis of foetal growth restriction was reported in 10.3% of cases, although the percentage of dead foetuses weighting <10° centile was at least twice in almost all gestational age periods. Post-mortem and placental histological examinations were carried out in more than 70% and more than 90% of cases, respectively.

Conclusions: the implementation of a population-based surveillance system with high participation rate of maternity units and the use of universally accepted definitions could improve the identification of stillbirth avoidable risk factors and potentially modifiable predisposing maternal conditions, highlighting issues of perinatal assistance in need of improvement.