British pill studies stress importance of relation between progestogen content and vascular disease.
D000328:Adult; D002318:Cardiovascular Diseases / Q000139:chemically induced*; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D006801:Humans; D045167:Progesterone Congeners / Q000009:adverse effects*; D006113:United Kingdom
D003276:Contraceptives, Oral; D045167:Progesterone Congeners