Analysis of the STRAW Operational Definition of the Early Menopausal Transition

Abstract

Researchers of menopause and the menopausal transition do not share uniform operational definitions. The Stages of Reproductive Aging Workshop (STRAW) proposed a conceptual framework and operational definitions for women's reproductive aging to address this problem. Our study evaluated the STRAW definition of entry into the menopausal transition, namely, a persistent increase in menstrual cycle variability operationally defined as a difference of 7 days or more between the lengths of one cycle and the next that repeats in no more than 10 menstrual cycles. We studied a random subset of women in the Tremin Trust research database. Tremin is a longitudinal study in which women prospectively record on calendar cards when they are and are not menstruating. We selected 144 women for whom data were recorded from age 20 through the close of menstrual life. We found that every woman met the STRAW criterion when she was aged 40+, but the great majority also met the criterion when aged 20–29 (87%) and 30–39 (78%). We then conducted further analyses of the distribution of STRAW events throughout the lifespan. In conclusion, the STRAW-recommended criterion does not provide an optimal operational definition marking entry into a menopausal transition.