title: Letter: Thromboembolism, oral contraceptives, and oestrogen concentration gradient.
mesh_terms: D000498:Allyl Compounds / Q000008:administration & dosage / Q000009:adverse effects; D003276:Contraceptives, Oral / Q000008:administration & dosage / Q000009:adverse effects*; D003281:Contraceptives, Postcoital / Q000008:administration & dosage; D045166:Estradiol Congeners / Q000008:administration & dosage / Q000009:adverse effects*; D004963:Estrenes / Q000008:administration & dosage / Q000009:adverse effects*; D004967:Estrogens / Q000378:metabolism; D005260:Female; D006801:Humans; D006914:Hydroxysteroids / Q000008:administration & dosage / Q000009:adverse effects; D008598:Menstruation; D010053:Ovary / Q000502:physiology; D045167:Progesterone Congeners / Q000008:administration & dosage / Q000009:adverse effects*; D013923:Thromboembolism / Q000139:chemically induced*; D013997:Time Factors
chemical_list: D000498:Allyl Compounds; D003276:Contraceptives, Oral; D003281:Contraceptives, Postcoital; D045166:Estradiol Congeners; D004963:Estrenes; D004967:Estrogens; D006914:Hydroxysteroids; D045167:Progesterone Congeners