Adrenal Histologic Stress-related Changes in Third Trimester Stillbirth. 
Adrenal histologic changes, including compact cell change (CCC), cystic change (CYC), and adrenal hemorrhage (AH), and their clinical correlations have only infrequently been investigated in stillbirth.  We evaluated 75 third trimester singleton stillborns with complete autopsies (30 term and 45 preterm).  A total of 58 had unexplained stillbirth and 17 had clinical placental abruption.  The mothers were predominantly African-American (89%).  CCC and CYC were diagnosed as cytoplasmic eosinophilia and cystic cavities in the definitive cortex, respectively.  Adrenal changes were correlated with acute thymic involution (ATI), thymic petechiae, and clinical features, including abruption.  CCC, CYC, and AH were present in 58 (77%), 51 (68%), and 15 (20%) of the 75 stillborns, respectively.  CCC and CYC were frequently seen together ( P < .001).  CCC and CYC were associated with higher ATI grade ( P < .001 and P = .010, respectively).  The presence of CCC, but not CYC, was associated with absence of thymic petechiae ( P = .013) and was more frequent with unexplained stillbirth compared to abruption ( P = .017).  AH was associated with lower ATI grade ( P = .002), with thymic petechiae ( P < .001), and with abruption ( P = .004).  CYC was associated with diabetes ( P = .015).  Overall, CCC and CYC were frequent findings and correlated with higher ATI grade, suggesting similar causes and time frames.  CCC, but not CYC, correlated with unexplained stillbirth compared to abruption, but its high frequency in both groups limits its usefulness in their separation.  AH was more frequent in the abruption group and correlated with lower ATI grade and thymic petechiae, supporting an association with sudden asphyxial death.