New model may pinpoint last menstrual period
Results of a just-published study indicate a possible method to predict when a woman will have her final menstrual period.1 Such findings might be helpful in aiding women and providers in combatting potential bone loss and cardiovascular risk associated with onset of menopause.
Clinicians monitor bleeding patterns to determine when a woman is entering the menopause transition stage. However, this transition stage is an imprecise predictor of when the final menstrual period will take place. It is estimated that more than 60% of women who are classified as being in early menopause (when periods are less predictable, but there are no big gaps in cycles) become postmenopausal without any additional clinical bleeding signal.1
Many women going through the transition ask their clinicians when they will reach menopause and stop menstruating, says Arun Karlamangla, MD, assistant professor in the David Geffen School of Medicine at the University of California in Los Angeles (UCLA). Providers as yet have a good way of telling women how close they are to having their last menstrual cycle, says Karlamangla, a co-author of the current study. Even women who already have had their last cycle will not know for sure if it was the last one until 12 months have passed, he notes.
“This study was designed to test if such information could be gleaned from measurements of their hormones and comparing them to previous measurements of the same hormones when menstrual cycling was regular,” Karlamangla says.
Being able to estimate when the final menstrual period will take place has taken on importance beyond just helping women gauge when they will stop having periods, said the study’s lead author, Gail Greendale, MD, professor of medicine in the division of geriatrics at the David Geffen School of Medicine at UCLA. “We know that potentially deleterious physiological developments, such as the onset of bone loss and an increase in cardiovascular risk factors, precede the final menses by at least a year,” said Greendale in a release accompanying the study’s publication.
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To conduct the study, the researchers analyzed longitudinal data collected annually for up to 11 years from 554 women taking part in the National Institutes of Health’s Study of Women’s Health Across the Nation.
At enrollment, the women were between the ages of 42 to 53, had an intact uterus and at least one ovary, were not using medications affecting ovarian function, and had experienced at least one menstrual period in the prior three months. Scientists then looked at levels of estradiol and follicle stimulating hormone (FSH). Why? The level of FSH starts increasing and estradiol starts decreasing about two years prior to the final menstrual period, or about a year before the rise of bone loss and cardiovascular risk factors.2,3
Results of the analysis indicate the levels of the two hormones could be used to estimate whether women were within two years of beginning their final menstrual period, within one year, or beyond their final period.
Researchers note the study had some limitations, including its modest sample size. Also, hormone levels were sampled once a year. More frequent sampling might have allowed a more precise estimate of a woman’s place on the timeline.
What’s the next step?
Being able to predict a woman’s final menstrual period could have broader implications for women’s health, said Greendale. In the year leading up to the final menstrual period, women face accelerated bone loss and increased cardiovascular risk, she noted.
“For example, some researchers have proposed that an intervention begun one or two years before the final menstrual period would greatly decrease future fracture risk by preventing the very rapid bone loss that occurs in the few years before and few years after the final menses,” Greendale said. “But before ideas such as this can be tested, we need to accurately predict where a woman is in her timeline to menopause.”
What is the next step in research? Karlamangla says researchers will need to validate the method in another cohort of women.
“Once it has been validated, web-based calculators can be made available for doctors and their patients to use to determine where a woman is on the timeline to menopause,” he states.
1. Greendale GA, Ishii S, Huang MH, et al. Predicting the timeline to the final menstrual period: the study of women’s health across the nation. J Clin Endocrinol Metab 2013. Doi: 10.1210/jc.2012-3732.
2. Matthews KA, Crawford SL, Chae CU, et al. Are changes in cardiovascular disease risk factors in midlife women due to chronological aging or to the menopausal transition? J Am Coll Cardiol 2009; 54:2,366-2,373.
3. Greendale GA, Sowers M, Han W, et al. Bone mineral density loss in relation to the final menstrual period in a multi-ethnic cohort: results from the Study Of Women’s Health Across The Nation (SWAN). J Bone Miner Res 2012; 27:111-118.