Letter: Withdrawal of Serial C.
D003276:Contraceptives, Oral / Q000009:adverse effects*; D003277:Contraceptives, Oral, Combined / Q000009:adverse effects*; D003279:Contraceptives, Oral, Sequential / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D006801:Humans
D003276:Contraceptives, Oral; D003277:Contraceptives, Oral, Combined; D003279:Contraceptives, Oral, Sequential; D004967:Estrogens