Abstract
In 169 consecutive women undergoing cesarean section, of which 90 were performed as an emergency and 79 electively, the frequency of deep vein thrombosis was evaluated with a non-invasive diagnostic technique - strain gauge plethysmography. Three patients developed thrombosis (1.8 per cent), all after acute surgery. No specific background factors were associated with the development of thrombosis. In 26 of the 79 patients (33 per cent), who were plethysmographed before operation, a biphasic venous emptying indicated venous outflow obstruction by the pregnant uterus.