Several menopausal staging definitions are currently being used in ongoing studies designed to identify changes occurring during menopause. The objective of this study was to determine which definition captures the earliest hormonal changes in the menopausal transition.
In this prospective cohort study, women aged 35 to 47 years were followed for 5 years. Women were classified as premenopausal, early transition, late transition, and postmenopausal by 2 different menopausal staging systems defined by bleeding patterns. Definitions from the Study of Women Health Across the Nation (SWAN) and Stages of Reproductive Aging Workshop (STRAW) were compared. A new menopausal staging system (PENN-5) was also developed with five groups rather than four to distinguish among women with more subtle changes in cycle length. For each staging system, a linear regression model was created comparing mean hormone values (inhibin B, FSH, LH, E2) and menopausal stages at each assessment. Race, body mass index, cycle day, smoking, and follow-up time were included in the model.
Statistically significant differences in mean inhibin B and FSH levels, but not estradiol levels, were detected between the earliest menopausal stages of each definition. Significant differences in LH values were detected among the earliest stages of the SWAN and STRAW definitions, but not the PENN-5 definition.
Subtle changes in menstrual cycle length reflect significant changes in inhibin B and FSH levels during the menopausal transition. Therefore, it appears that subtle changes in bleeding pattern may be helpful in identifying the earliest hormonal changes during menopausal transition.
Even a single change of at least 7 days in menstrual cycle length in late reproductive-age women is associated with significant changes in inhibin B and FSH levels. Therefore, in appears that subtle changes in bleeding pattern may be helpful in identifying the earliest changes during the menopause transition.
From Departments of 1Obstetrics/Gynecology and 2Psychiatry, 3Division of Reproductive Endocrinology and Infertility, 4Biostatistics and Epidemiology and Center for Clinical Epidemiology, 5Center for Research in Reproduction and Women's Health, 6Laboratory of the Clinical Research Center, University of Pennsylvania School of Medicine, Philadelphia, PA.
Received May 5, 2004; revised and accepted July 27, 2004.
This work was supported by grants from the National Institutes of Health, R01-1AG-12745 and 2MO1RR-00040-37 (General Clinical Research Center)
Address correspondence to: Clarisa R. Gracia, MD, PA Fertility Care, 3701 Market St, Suite 800, Philadelphia, PA 19104. E-mail: firstname.lastname@example.org