- Naturally postmenopausal women must not have had a menstrual period for at least six months, but less than 12 months, as confirmed by a blood test; or for at least 12 months with no blood hormone test confirmation. Naturally postmenopausal women must not have had a menstrual period since the age of 54. Surgically menopausal women must have undergone bilateral oophorectomy (removal of both ovaries) at least 5 months prior to the start of the study, and the surgical report may be requested to confirm the surgery date and that the surgery was not due to a cancerous condition.