Thymic pathology in placental abruption: an autopsy study of third trimester stillborns in a predominantly African–American population

Abstract

Objective: Complete placental abruption results rapidly in fetal death through acute asphyxia, and identification of thymic lesions at autopsy may help in confirming this diagnosis. Thymic petechiae are a marker for acute asphyxia, while absence of histologically identifiable acute thymic involution (ATI), which requires several hours to develop, may help in exclusion.

Methods: We identified autopsies on 17 3rd trimester stillborns with clinical abruption; 58 stillborns with unexplained demise comprised the control group. Eighty-nine percent of the mothers were African–American. ATI was graded 0–4 (grades 0–1 and 3–4 were combined for analysis), and thymic petechiae were recorded.

Results: In the abruption group, ATI grade 0–1 was more frequent than higher grades: 13 (77%) had ATI grade 0–1 compared to 1 (6%) with ATI grade 3–4 (p < 0.001). In contrast, in the control group, ATI grade 3–4 was more frequent than lower grades: 9 (16%) had ATI grade 0–1 compared to 30 (52%) with ATI grade 3–4 (p < 0.001). Thymic petechiae were more frequent in the abruption compared to control group [10 (59%) versus 2 (3%)] (p < 0.001), and were frequently seen with low ATI grade: 10 (83%) had ATI grade 0–1 (p < 0.001).

Conclusions: The presence of thymic petechiae and ATI grade 0–1 correlates significantly with a clinical diagnosis of placental abruption.

• Acute thymic involution
• fetal autopsy
• intrathoracic petechiae
• placental abruption
• stillbirth
• thymic petechiae

Declaration of interest

The authors report no declarations of interest.