- Females on hormone replacement therapy (HRT) and whose menopausal status is in doubt will be required to discontinue HRT to allow confirmation of post menopausal status prior to study enrolment. For most forms of HRT, at least 2 to 4 weeks will elapse between the cessation of therapy and the blood sampling; this interval depends on the type and dosage of HRT. Following confirmation of their post menopausal status, they can resume the use of HRT during the study without the use of a contraceptive method.