Women with Irregular Menstruation Have Increased Risk of Death From Ovarian Cancer

Barbara A. Cohn, PhD, MPH

Women with irregular menstrual cycles have a 2.4-fold increased risk of death from ovarian cancer, according to a large, prospective study presented at the 2014 AACR Annual Meeting.

“In this large, prospective study, we found that those who had irregular menstrual cycles had a 2.4-fold increased risk of death due to ovarian cancer,” Barbara A. Cohn, PhD, MPH, director of the Child Health and Development Studies at the Public Health Institute in Berkeley, California, said in a press release.“This information may help earlier diagnosis and perhaps lead to a strategy to prevent ovarian cancer by pointing toward how the cancer develops and spreads.”

The Child Health and Development Studies enrolled more than 15,000 pregnant women between 1959 and 1967, following them for more than 50 years to study factors impacting health during pregnancy. Data presented at the AACR Annual Meeting was based on 14,403 women from this study who had a single live birth. Medical reports and self-reported data were collected from these women on their menstrual irregularity, including those whose cycles were longer than 35 days, and those who experienced anovulation.

Of the 13% of women who said they had menstrual irregularities when they were 26 years old, 64 of them died from ovarian cancer. The average age of death by ovarian cancer was 69 years of age for these women, the study said.

“It is notable that the 2.4-fold increase in risk of ovarian cancer death we observed for women with irregular/infrequent cycles in this study is close to the threefold increase in risk observed for women with a family history of ovarian cancer in a first-degree relative,” explained Cohn. “Our study finding could lead to better understanding of the 90 percent of ovarian cancers that occur in women with no family history of ovarian cancer and with no known high-risk inherited mutations.”

The authors of the study said that the association between menstrual irregularities and ovarian cancer death was independent of age, race, parity, and weight. The association between menstrual irregularities and ovarian cancer death was stronger after the women reached their mid-60s.

Menstrual irregularities also increased the risk for serous- and endometrioid-type cancers by nearly threefold and fourfold, respectively. In addition, the incidence of late-stage ovarian cancer was found to be twofold higher for women with irregular or infrequent menstrual cycles.

These findings are contrary to the expectation that polycystic ovarian syndrome (PCOS), which is characterized by less frequent ovulation and irregular or long menstrual cycles, would protect the ovary. However, in addition to infrequent ovulation, there are a number of anatomical, hormonal, and metabolic abnormalities associated with PCOS that might account for the study findings, noted Cohn

“Among reproductive cancers, ovarian cancer is the most common cause of death, because it is usually diagnosed late in the disease process after it has spread,” said Cohn. “Unfortunately, there is no reliable method for early diagnosis or screening, and symptoms like abdominal pain and bloating often do not come to a woman’s attention until the cancer has spread.”