June 5 (HealthDay News) -- Bleeding disorders often go undiagnosed in women, say experts who've developed a new list of signs that might indicate a problem.

The guidelines aren't meant only for doctors. Women with heavy menstrual cycles should watch for these signs as well because about 25 percent of women with heavy menstruation have an undiagnosed bleeding disorder, said Dr. Andra James, an obstetrician at Duke University Medical Center and the study's lead author.

"Heavy bleeding should not be ignored," James said in a news release from the university. "When a woman's blood can't clot normally, the most obvious sign is a heavy period."

But in many such cases, doctors don't suspect a blood clotting problem. "Sometimes they think hormones are the cause, or fibroids," James said. "In some cases they recommend removal of the uterus or offer another gynecologic explanation when the real contributing factor is a blood clotting disorder."

The researchers recommended that doctors and women be on the lookout for:

• A personal history of heavy periods
• Blood disorders among family members
• Bruises when no injury has occurred
• Bleeding for more than five minutes with minor wounds
• Excessive or prolonged bleeding after dental extractions
• Surgical bleeding that is greater than expected
• Hemorrhaging that requires blood transfusions
• Postpartum hemorrhaging that occurs in the days after delivery

"Too often, women think heavy bleeding is OK because the women in their family -- who may also have an undiagnosed bleeding disorder -- have heavy periods as well," James said. "We want women who continually experience abnormal reproductive tract bleeding, specifically heavy menstrual bleeding, to be alert to these other signs and approach their physicians about being evaluated."

The guidelines appear online and in the July print issue of the American Journal of Obstetrics & Gynecology.

SOURCE: Duke University Medical Center, news release, June 2, 2009