Effects of Progestogen Oral Contraception with Norethisterone on Blood Clotting and PlateletsBr Med J 1972; 4 doi: https://doi.org/10.1136/bmj.4.5837.391 (Published 18 November 1972) Cite this as: Br Med J 1972;4:391
- L. Poller,
- Jean M. Thomson,
- P. W. Thomas
The effects on clotting tests and platelet function of six months' continuous administration of the 19-norsteroid, progestogen-only contraceptive, norethisterone, have been studied in four groups of women. In a group of women who have not previously taken oral contraceptive no acceleration of clotting or platelet factors was found, but in contrast a tendency to reduced coagulability was observed. Women who had previously been taking combined oestrogen-progestogen preparations showed reduced clotting and platelet parameters when norethisterone was substituted. No changes in clotting or platelets were found in women who changed from 17-acetoxysteroid progestogen chloramadinone acetate or in a group of women started postpartum.