Abstract

The administration of combined oestrogen/progestagen oral contraceptives raises blood levels of many factors concerned with blood coagulation^1–3 and increases the incidence of thrombo-embolism in healthy women,^{4 5} though the connection between these phenomena is obscure. Thrombo-embolism is also a post-operative complication, especially of pelvic surgery, and it seems quite likely that combined oral contraceptives may further increase the incidence of thrombosis after surgery. Prolonged rest in bed also predisposes to thrombosis and this risk too may be increased by such contraceptives. The incidence of thrombosis after surgery in women taking oral contraceptives is not yet known.