Three Cases of Intravascular Thrombosis

a causal relationship between oral contraceptive drugs and thrombotic disease (Chicago Conference, 1962; Mills, 1964). Laboratory investigations into the possible changes in the coagulation balance which might significantly add to the risk of thrombosis have yielded conflicting results. Phillips et al. (1961) studied the effects of exogenous steroids on the clotting mechanism of human subjects. Their results indicate that 19-nor-steroid compounds produce a significant rise in profibrinolysin and fibrinolysin levels and a less marked increase in antifibrinolysin. Recently Egeberg and Owren (1963) reported that norethynodrel in recommended contraceptive dosage produced an increased coagulability of the blood as evidenced by shortened plasma cephalin time, greatly increased antihaemophilic A factor, and slight increase in proconvertin activity' In addition, an increase in fibrinogen concentration was noted by Brakman and Astrup (1964). On the other hand, Sobrero et al. (1963) were unable to demonstrate any alteration in coagulation factors. Although the pathogenetic relation between 19-nor-steroid compounds and thrombosis has not been clearly defined, increasing reports of thrombosis in patients receiving this medication are of grave concern (Gaylis and Kramer, 1962; Lorentz, 1962 ; McIntyre et al., 1962; Richman, 1962; Staddon, 1962; McWilliam et al., 1963 ; Minogue et al., 1963; Reed and Coon, 1963; Cohen and Sajid, 1964; Schatz et al., 1964; StewartWallace, 1964; Zilkha, 1964; Baines, 1965; Hartveit, 1965; Leather, 1965).