Calcification of umbilical artery: two distinct lesions.

The clinical and pathological features of five cases of calcification of umbilical cord vessels were reviewed. Two distinct lesions were identified: calcification could produce either sclerosis of the wall or obliteration of the lumen. In three cases there was calcification within the media and adventitia of the umbilical arteries, with extension into Wharton's jelly in one case. The pathogenesis of this pattern of calcification--the sclerotic variant--is unclear but the findings of inflammation in the umbilical cord and its vessels, membranes, and decidua suggest intrauterine infection. In two cases there was complete calcification of umbilical arterial lumina resulting in total obliteration. The findings of fetal vessels in the chorionic plate with medial calcification in one of these two cases raises the possibility of thrombosis within the umbilical cord vessels as a cause, but the latter was not found. One infant from each group was liveborn. Both had shown signs of fetal distress in utero and delivered prematurely. The other three pregnancies resulted in macerated stillbirth preterm.