The hypercoagulable state in pregnancy is partly caused by the increased activity of factor VII in plasma. We demonstrate here that this activity is reduced to levels similar to those in plasma from non-pregnant women by highly purified phospholipase C from Bacillus cereus, i.e. the activity increase is due to a circulating complex of factor VII and a phospholipase C-sensitive compound. Phospholipase C had no effect on the levels of factor II and X in blood from pregnant women. This novel form of activated factor VII is not inhibited by an antiserum to the protein component of thromboplastin (apoprotein III). By gel filtration of plasma from pregnant women on Sephadex G-100 the phospholipase C-sensitive complex was partly separated from non-phospholipase sensitive factor VII also present in the same plasma.