The SFMWHS aimed to describe changes in the biopsychosocial health of midlife women through the menopausal transition. Almost 350 women living in the San Francisco Bay area in California, United States of America, were recruited from the community, including 89 African American, 164 European American, and 94 Mexican/Central American women. Participants were eligible if they were between 40 and 50  years of age and still experiencing regular menstrual cycles. Baseline data were collected at enrolment between 1996 and 1997, and women were followed up in person or via phone every 2 to 5 months for 5 years or until one year after the participant’s last menstrual period.