Menstrual Patterns Best Indicator of Aging Path

Changes to the menstrual cycle remain the most important clinical indicators of women's reproductive aging, according to new standardized staging criteria.

The changes identified by the most recent Stages of Reproductive Aging Workshop are now defined in 10 stages, whereas the 2001 STRAW criteria had 7. The new criteria, STRAW-10, offer more detail on the characteristics of flow and cycle length at each stage, along with corresponding endocrine changes. The article was published in Menopause, Climacteric, Fertility and Sterility, and the Journal of Clinical Endocrinology and Metabolism.

The late reproductive stage is now subdivided into two stages, −3b and −3a, instead of only stage −3 as before (Menopause 2012 Feb. 16 [doi:10.1097/gme0b013c31824d8f40]). In stage −3b, flow remains regular, whereas in stage −3a there are subtle changes in flow and length of cycle.

The postmenopausal stage +1, identified in the earlier STRAW criteria, also has been subdivided into three lettered stages, with the endocrine changes and duration of each stage described.

Unlike the previous STRAW criteria, the menstrual changes identified in STRAW-10 are relevant to any healthy woman, regardless of ethnicity, age, body mass index, or lifestyle, the researchers said, noting that although factors such as smoking status and BMI may affect the timing of menopause, the bleeding patterns remain reliable indicators of the reproductive stage.

“Despite the availability of blood tests and sonograms, the menstrual cycle remains the single best way to estimate where a woman is along the reproductive path,” said Dr. Margery Gass, a STRAW-10 coauthor, executive director of the North American Menopause Society (NAMS), and editor of Menopause.

“According to STRAW-10, most women (and their clinicians) can use the changes in their menstrual pattern to determine how close they are to menopause: late reproductive phase (subtle changes in cycle length and blood flow), early menopause transition (menstrual period 7 or more days early or late), and late menopause transition (the occurrence of more than 60 days between cycles),” Dr. Gass said in an interview.

STRAW-10 incorporates three biomarkers, anti-Müllerian hormone (AMH), inhibin B, and antral follicle count, which were not mentioned in the original STRAW criteria, along with follicle-stimulating hormone (FSH), which was included in the original criteria.

In developing the new criteria, an international group of 41 researchers, led by epidemiologist Siobán D. Harlow, Ph.D., of the University of Michigan, Ann Arbor, evaluated data from cohort studies of midlife women with the aim to incorporate the scientific findings of the past decade on ovarian aging and its endocrine and clinical indicators.

Although much has been learned since 2001 with regard to biomarkers, Dr. Harlow and colleagues said that the biomarker criteria outlined in STRAW-10 must still be considered “supportive,” in part because more research is needed and because of the invasiveness and expense of testing.

Dr. Gass said that checking hormone levels is not necessary “except in women who have undergone endometrial ablation or hysterectomy, or who have unusual health circumstances.”

Women for whom the STRAW-10 criteria do not apply include those with polycystic ovarian syndrome or hypothalamic amenorrhea. Women with chronic illnesses such as HIV-AIDS, or those undergoing certain types of cancer treatments, also are difficult to assess under STRAW-10, as cycles and hormone levels can change in response to medication.

The new criteria do not use age to determine reproductive staging, but women younger than 40 years who have premature ovarian insufficiency or premature ovarian failure do not fit well under STRAW-10, the researchers noted, as their course of reproductive aging is more variable.

STRAW-10 meetings were funded by the National Institutes of Health, the Department of Health and Human Services through the National Institute on Aging (NIA) and the Office of Research on Women's Health, NAMS, the American Society for Reproductive Medicine (ASRM), the International Menopause Society in Cape Town, South Africa, and the Endocrine Society.

Dr. Gass receives support from NAMS. Dr. Harlow disclosed ties with the NIA, NAMS, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Other coauthors dislcosed ties with the Endocrine Society, ASRM, the NIA, NAMS, and various pharmaceutical companies.

With STRAW-10, most women can use the changes in their menstrual pattern to find how close they are to menopause.

Source DR. GASS

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STRAW-10 Will Spur More Research

The main changes [in STRAW-10] have to do with the late reproductive stage and the early postmenopausal stage, which has been subdivided to give more detail, and in turn help understand the physiologic changes which occur at these times. In particular, the late reproductive stage has been subdivided so the measurement of the anti-Müllerian hormone (AMH) and follicle count can be used as a measure of decreased fertility, but the menstrual bleeding is still regular and unchanged. Inhibin B also may be low.