Patterns of breaks in umbilical cords by different mechanisms*

Investigations of perinatal deaths often result in discrepancies between autopsy findings and witness accounts. The mechanism by which the umbilical cord is severed after delivery is a common quandary. Confirming or refuting the mother's stated method frequently has significant investigative importance; however, a surprising paucity of data currently exists to allow an objective opinion about the likely mechanism. Ninety-nine placentas with umbilical cords were examined. By random selection, each cord was severed by one of the following tools or mechanisms: knives, scissors, traction, or crush. Each break was examined and photographed, and a tissue section from the broken end examined microscopically. Differentiation of mechanism was best done grossly based on specific pattern recognition. Umbilical cords severed by blunt force have distinctly different morphology from those severed by sharp force. Even similar-appearing sharp force transections frequently have mechanism-specific distinctive patterns of injury.