The Journal of clinical endocrinology and metabolism
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J. Clin. Endocrinol. Metab. · Jun 2004
Multicenter Study Comparative StudyBody size and ethnicity are associated with menstrual cycle alterations in women in the early menopausal transition: The Study of Women's Health across the Nation (SWAN) Daily Hormone Study.
The dynamics of reproductive hormones that characterize the menopausal transition (perimenopause) are incompletely understood, particularly in non-Caucasian women. The Study of Women's Health across the Nation (SWAN) is a multiethnic cohort study of 3302 women at seven sites who were aged 42-52 yr at baseline. All participants are seen annually to assess a variety of endpoints. ⋯ When compared with cycles of younger control women, the cycles of the SWAN DHS participants had higher gonadotropins, lower total integrated Pdg, and E1c levels that were not different, which suggests that the ovary retains sensitivity to elevated FSH in the early menopausal transition. In this cross-sectional study of women over age 42 who are premenopausal or in the early menopausal transition, there were important differences in the characteristics of cycles related to age, body mass index, and ethnicity. Comparisons to younger women indirectly support the inhibin hypothesis, which proposes that the initiating event in the menopausal transition is the loss of inhibin negative feedback on FSH secondary to a diminished follicular reserve.