Thromboplastin activity in blood monocytes from oral contraceptive users.

The thromboplastin activity in blood monocytes from 13 women on oral contraceptives and from a reference group of 20 women not on oral contraceptives has been compared. The thromboplastin activity in endotoxin-stimulated monocytes from the oral contraceptive (OC) users was on average 54% of the activity in the reference group (p less than 0.05). The thromboplastin activity in unstimulated monocytes was also lower in the OC group than in the reference group although not statistically significant. Factor VII was significantly higher (p less than 0.05) in the OC group, whereas no difference was observed in fibrinogen and factor V levels.