The investigators explored the potential of the picoAMH enzyme-linked immunosorbent assay (ELISA) research-use-only product (Ansh Labs) using data for 1,537 middle-aged women enrolled in the prospective, longitudinal Study of Women's Health Across the Nation (SWAN). Among many other kinds of health assessments tracked over time during the menopause transition period, SWAN entailed blood testing for AMH, an ovarian hormone, and follicle-stimulating hormone (FSH), a pituitary hormone.
For the analysis, the researchers explored associations between AMH and FSH results at baseline during premenopause or early perimenopause and at the time of the final menstrual period for women ages 42 to 63. At the time the analysis was conducted, two authors were employees of Ansh Labs.
The group found an association between lower AMH levels and the nearness of menopause in women in their late 40s and early 50s. Furthermore, the areas under the receiver operating characteristic curves (AUCs) for predicting the final menstrual period within two years or 36 months were significantly better -- though the differences were small -- for AMH versus FSH.
If the AMH level was lower than 10 pg/mL, the likelihood of having a final menstrual period within a year was 51% for women younger than 48 years and 79% for those older than 51, the researchers found. Conversely, levels greater than 100 pg/mL signified a low likelihood of having a last menstrual period within a year for women in their late 40s and early 50s.
"A high AMH value is particularly good at excluding an imminent [final menstrual period]," co-lead author Dr. Nanette Santoro, chair of obstetrics and gynecology at the University of Colorado, and colleagues noted.
AMH vs. FSH
The predictive capability was made possible by the sensitivity of the particular AMH test used in the study, according to the researchers. The test has a lower limit of detection than other assays, and levels that were previously undetectable are now registered, they explained.
Compared with FSH, advantages of testing AMH include direct measurement of ovarian activity and the fact that AMH levels are "stable across the menstrual cycle and can be measured at any time without affecting interpretation of its level," the authors noted. FSH testing needs to be done during the first five days of the onset of bleeding, which requires another visit to the lab. That's inconvenient and subject to misinterpretation by the patient, Santoro commented by email to LabPulse.com.
"Since AMH does not depend on the timing within the cycle, I can get the level at the same time as the office visit," she noted. "So practically speaking it's a big improvement."
Knowing the timing of a final period can be helpful in many ways to women nearing menopause, particularly against the backdrop of longer life spans. Currently, the mean age of a final menstrual period is 51.
"AMH measurements may help women predict when vasomotor symptoms are likely to begin, or when heavy menstrual bleeding is likely to end," the authors wrote. "In women with heavy bleeding due to uterine pathology, such as leiomyomata or adenomyosis, the ability to predict the [final menstrual period] accurately may help women to decide whether to undergo a hysterectomy or temporize with medical management," they added.
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