Hormones and Cognition in the Menopausal Transition

Inclusion Criteria:

Menopausal status will be based on self-report of menstrual cycles over the past 12 months. Early perimenopause is defined as the presence of irregular periods (cycle length differs by 7 days from usual). Late perimenopause is defined as at least 2 skipped periods over the past 12 months (cycle double usual length) and one period of amenorrhea (over 60 days without a period), with at least one menstrual cycle over the past 12 months, according to the Stages of Reproductive Aging Workshop criteria.

Exclusion Criteria:

- history of neurological disease known to affect cognitive function (i.e., stroke, MS, etc) and major psychiatric illness. The investigators will exclude women who are currently pregnant or breast-feeding, have undergone surgical menopause, or who have used exogenous hormone preparations affecting ovarian or pituitary function in the past 3 months. The investigators will also exclude women who have had hysterectomies, but intact ovaries, or oophorectomies. Women who choose to initiate HRT at some point during the study will continue to be followed, but their data obtained after HRT is initiated will be analyzed separately.