Source: Neuropsychopharmacology  |  Posted 9 years ago

Episodes of anovulation prompted by menstrual disturbances should be evaluated separately from those resulting from pregnancy or oral contraceptive, say researchers in the United States.

Obtaining additional details on menstrual factors that affect lifetime ovulatory cycles (LOC), particularly data on missed or irregular cycles, provides critical information on women's ovarian cancer risk, these investigators from Duke University Medical Center, Durham, North Carolina, have found.

In this population-based study of ovarian cancer, Dr P G Moorman and colleagues from Duke's Cancer Prevention, Detection, and Control Research Program, Department of Community and Family Medicine compared the standard method for calculating LOC with a second method in which more detailed information on menstrual characteristics is obtained.

To determine if the additional data results in stronger links with ovarian cancer, the researchers reviewed data from 232 cases and 242 controls and used unconditional logistic regression to estimate odds ratios for ovarian cancer by number of LOC.

Average number of LOC was 29 fewer for the method in which more detailed menstrual cycle information was obtained as compared with the standard method (p < 0.0001). This difference was largely the effect of the inclusion in the second method of information about episodes missed/irregular periods.

Links between LOC and ovarian cancer were weaker for the second method than the standard method. Further analyses indicated a reduced number of ovulatory cycles as result of menstrual irregularity was linked with increased ovarian cancer risk. This was on contrast to the protective effects observed for fewer ovulatory cycles due to pregnancy or oral contraceptive use.