What can increase the flow of blood during menstration?

Blood thinners: Women on blood thinners or taking too much Aspirin can sometime have heavier flow. Some medical conditions can cause the blood to not clot well . But i think you would have been diagnosed by now if that were the case.

Herbals: Many herbal supplements also act as blood thinners, such as ginko biloba, ginsing, garlic, and others. Also increased bleeding can be due to the development of an endometrial polyp or other urerine abnormality or infection. If this is a recurring thing you should see your gyn to be evaluated.