A new study from researchers at the University of Iowa has found that shortened times between menstrual periods may be an initial sign of menopause, while heavy bleeding seems to have other causes.
The researchers found that a shortened interval between periods, fewer than 21 days, in women aged 42 to 52 indicated the women were in the early stages of menopause. These periods were often “anovulatory”, meaning the women did not ovulate even though they experienced bleeding. The researchers, led by Dr. Bradley Van Voorhis of the University of Iowa College of Medicine in Iowa City, also found that longer intervals between periods, in excess of 36 days, were more common later in menopause.
Heavy bleeding appeared to be unrelated to ovulation, according to the study, and was often seen in women who were obese or had uterine fibroids, non-cancerous growths that can cause pain and heavy menstrual bleeding.
The study examined 804 women in the United States over a three year time period. The women gave periodic urine samples to determine whether they were ovulating, and also kept track of their monthly menstrual patterns.
The women were then separated into two groups: those with unpredictable periods during the past three months, a sign of early menopause, and those who’d skipped two or more periods, a sign of the later phases of menopause.
The researchers found that short intervals between periods were more common among women in early menopause, with 44 percent of their periods anovulatory. Longer intervals were more common in late menopause, with two-thirds of those periods being anovulatory. Women with short or long periods, either fewer than four days or more than seven days, also commonly had anovulatory cycles.
However, the study found that women with heavy periods had relatively few anovulatory cycles, which suggested the heavy bleeding was not typically related to hormonal changes.
The researchers said the study suggests that a woman in early menopause with abnormal timing in her periods, either short or long intervals, or a short or long duration, is likely having anovulatory cycles.
“In contract, if the complaint is only heavy bleeding, anovulation is less likely and careful evaluation for structural lesions including polyps and fibroids is warranted,” the researchers wrote in a report about the study, published in the journal Obstetrics & Gynecology.
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