No abstract

British MedicalJournal, 1969, 4, 273-274 ummary: Platelet aggregation has been found to be significantly accelerated with the coagulation-inducedChandler's tube technique in women taking combined oestrogen-progestin oral contraceptives, though this was less than in the third trimester of pregnancy. Women taking the pure progestogen, chlormadinone acetate, have not shown this change up to the sixth month of study. In contrast the accelerated platelet aggregation resulting from conventional oral contraception became normal one month after changing to the progestogen. There was no change in the platelet aggregation response to adenosino diphosphate (A.D.P.) during oral contraception. IntroductionOral contraception with conventional oestrogen-progestin preparations results in rises of clotting factors, including factor X, which is involved in the " intrinsic " clotting system (Poller and Thomson, 1966). When this mechanism is accelerated by physical exertion the platelet aggregation time may also be shortened (Poller et at., 1969c).We therefore carried out studies in women taking a variety

1. Platelet aggregation in the Chandler's tube has been found to be increased in a group of normal male and female volunteers who undertook strenuous physical exercise. This coincided with acceleration of the ‘intrinsic’ blood clotting system and a rise in fibrinogen. The rise in fibrinogen occurred despite increased fibrinolysis. 2. The study confirms the sensitivity of the platelet aggregation system to changes in the ‘intrinsic’ clotting mechanism. Acceleration of this system in this study resulted from a physiological cause and produced accelerated aggregation in the coagulation‐affected phase.

No abstract

No abstract