“…This syndrome has been associated with many disparate conditions, such as pregnancy toxaemia, septicaemia, amniotic fluid embolism, hypertension, snake bite and shock (e.g., the reviews by Pitney, 1971 and Simpson and Stalker, 1973 Pregnancy is associated with changes in the fibrinogen/plasminogen system, although the details are still subject to dispute probably related to technical differences (Woodfield et al, 1968;Bonnar et al, 1969). A variety of changes in coagulation factors and their inhibitors have been observed in patients receiving oestrogen-progestogen preparations (e.g., Brackman and Astrup, 1964;Ygge et al, 1969;Howie et al, 1970). Whereas the precise mechanism of an enhanced thrombotic tendency is still disputed, its existence is sufficiently well established to provide a good theoretical basis for the observed clinical association, particularly related to the oestrogen content of the pill (British Medical Journal, 1974).…”