Estimating the time of death in stillborn fetuses: I. Histologic evaluation of fetal organs; an autopsy study of 150 stillborns.

OBJECTIVE: To determine whether the autopsy histology of fetal tissues can determine the time of death of stillborn fetuses.
METHODS: Hematoxylin and eosin slides from autopsies of 150 stillborn fetuses with well-timed deaths were evaluated retrospectively. Fetuses were divided into a learning set (100 fetuses) and a test set (50 fetuses).
RESULTS: From assessment of the 100 fetuses in the learning set, 23 histologic features were identified with possible temporal associations with fetal death. When those histologic features were randomly and blindly assessed in the 50 test fetuses, ten features performed well as diagnostic tests (sensitivity, specificity, and positive predictive values at or above 0.875), correctly classifying 43 of 50 fetuses (86%) with respect to the time of death. The ten histologic features and their predicted death-to-delivery intervals were: loss of nuclear basophilia in individual cells in renal cortical tubules (4 hours), liver (24 hours), inner half of the myocardium (24 hours), outer half of the myocardium (48 hours), bronchial epithelium (96 hours), and tracheal cartilage (1 week); and loss of nuclear basophilia of all cells in the liver (96 hours), gastrointestinal tract (1 week), adrenal (1 week), and kidney (4 weeks). The development of these histologic changes appeared to be accelerated by fetal hydrops and a delivery-to-autopsy interval exceeding 24 hours and decelerated by fetal gestational age under 25 weeks.
CONCLUSION: Histologic changes identifiable in hematoxylin and eosin-stained fetal tissue may be useful for estimating the time of death in many stillborn fetuses.