Total Macroscopic Maceration Score (TMMS): A Proposal for the Assessment of Maceration in Stillbirths

Abstract

In forensic pathology, estimating the timing of intrauterine death in stillbirths is still challenging. The current gold standard methods involve the macroscopic assessment of fetal maceration integrated with the histological examination of the fetus and placenta. This study proposes a maceration scoring system and its predictive value in estimating the postmortem interval (PMI) in stillbirths. A retrospective analysis was conducted on stillbirths delivered between 2017 and 2024. Circumstantial, clinical, postmortem data, and color photographs taken at delivery and/or autopsy, were collected. A total macroscopic maceration score (TMMS), ranging from 4 to 20, was developed and applied to photographs of 52 stillbirth cases. The association between TMMS and PMI, calculated at delivery (dPMI) and at post-mortem examination (pPMI) was evaluated, and a cross-validation was performed. TMMS values ranged from 4 to 20 and showed high interobserver agreements (from 88% to 93%). The correlation between TMMS and pPMI was stronger than that with dPMI, and was best described by a second order polynomial regression, with an R² value of .958 and a mean absolute error of 0.39 days. The TMMS showed promising results and, when integrated with current gold-standard methods, it may be an additional tool to assess the PMI in stillbirths.