Knotted umbilical cord as a cause of death in a Cercopithecus aethiops fetus.

A knotted umbilical cord was found in a third trimester Cercopithecus aethiops abortus. On the maternal side of the knot, the umbilical cord was engorged with blood. The umbilical cord on the fetal side of the knot was devoid of blood, suggesting that the knot may have occluded blood flow to the fetus.