In questionable cases a blood sample with simultaneous follicle stimulating hormone (FSH) >40 milliinternational units (MlU)/milliliter (mL) and estradiol <40 picograms (pg)/mL (<147 picomole [pmol]/liter [L]) is confirmatory). Females on hormone replacement therapy (HRT) must discontinue HRT to allow confirmation of post-menopausal status before study enrollment. For most forms of HRT, at least 2 to 4 weeks should elapse between the cessation of therapy and the blood draw; this interval depends on the type and dosage of HRT. Following confirmation of their post-menopausal status, they can resume use of HRT during the study without use of a contraceptive method.