Stillbirth diagnosis and classification: comparison of ReCoDe and ICD-PM systems

The identification of causes of stillbirth (SB) can be a challenge due to several different classification systems of SB causes. In the scientific literature there is a continuous emergence of SB classification systems, not allowing uniform data collection and comparisons between populations from different geographical areas. For these reasons, this study compared two of the most used SB classifications, aiming to identify which of them should be preferable.

A total of 191 SBs were retrospectively classified by a panel composed by three experienced-physicians throughout the ReCoDe and ICD-PM systems to evaluate which classification minimizes unclassified/unspecified cases. In addition, intra and inter-rater agreements were calculated.

ReCoDe defined: the 23.6% of cases as unexplained, placental insufficiency in the 14.1%, lethal congenital anomalies in the 12%, infection in the 9.4%, abruptio in the 7.3%, and chorioamnionitis in the 7.3%. ICD-PM defined: the 20.9% of cases as unspecified, antepartum hypoxia in the 44%, congenital malformations, deformations, and chromosomal abnormalities in the 11.5%, and infection in the 11.5%. For ReCoDe, inter-rater was agreement of 0.58; intra-rater agreements were 0.78 and 0.79. For ICD-PM, inter-rater agreement was 0.54; intra-rater agreements were of 0.76 and 0.71.

There is no significant difference between ReCoDe and ICD-PM classifications in minimizing unexplained/unspecified cases. Inter and intra-rater agreements were largely suboptimal for both ReCoDe and ICD-PM due to their lack of specific guidelines which can facilitate the interpretation. Thus, the authors suggest correctives strategies: the implementation of specific guidelines and illustrative case reports to easily solve interpretation issues.