the cyclical sequential regimen employed was determined by the dosage of oestrogen prescribed during the initial six-month period : norethisterone ( 2.5 mg or 5.0 mg ) on days sixteen to twenty-one of cyclical treatment with oestrone piperazine sulphate or conjugated equine oestrogens , and dl-norgestrel ( 0.5 mg daily ) from day twelve to day twenty-one of cyclical oestradiol valerate treatment .
C0014939
oestrogen
C0014938
conjugated