title: Effects of progestogen oral contraception with norethisterone on blood clotting and platelets.
abstract: 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.
mesh_terms: D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000187:drug effects*; D002715:Chlormadinone Acetate; D003276:Contraceptives, Oral / Q000494:pharmacology*; D004338:Drug Combinations; D004967:Estrogens; D005167:Factor VII / Q000032:analysis; D005170:Factor X / Q000032:analysis; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D009640:Norethindrone / Q000494:pharmacology*; D010714:Phosphatidylethanolamines; D010973:Platelet Adhesiveness / Q000187:drug effects; D049590:Postpartum Period; D011247:Pregnancy; D011372:Progestins; D011517:Prothrombin Time
chemical_list: D003276:Contraceptives, Oral; D004338:Drug Combinations; D004967:Estrogens; D010714:Phosphatidylethanolamines; D011372:Progestins; D002715:Chlormadinone Acetate; D005167:Factor VII; D005170:Factor X; D005340:Fibrinogen; D009640:Norethindrone