Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent stroke in people who have atrial fibrillation, valvular heart disease, or artificial heart valves. Less commonly, it is used following ST-segment elevation myocardial infarction and orthopedic surgery. It is generally taken by mouth, but may also be used intravenously.The common side effect is bleeding. Less common side effects may include areas of tissue damage and purple toes syndrome. Use is not recommended during pregnancy. The effects of warfarin typically should be monitored by checking prothrombin time (INR) every one to four weeks. Many other medications and dietary factors can interact with warfarin, either increasing or decreasing its effectiveness. The effects of warfarin may be reversed with phytomenadione (vitamin K1), fresh frozen plasma, or prothrombin complex concentrate.Warfarin decreases blood clotting by blocking an enzyme called vitamin K epoxide reductase that reactivates vitamin K1. Without sufficient active vitamin K1, clotting factors II, VII, IX, and X have decreased clotting ability. The anticlotting protein C and protein S are also inhibited, but to a lesser degree. A few days are required for full effect to occur, and these effects can last for up to five days.
Endometrial hyperplasia, included in this PALM category of abnormal bleeding, is more common in women who are obese or who have a history of chronic anovulation. When endometrial hyperplasia is associated with atypical cells, it can progress to cancer or occur concurrently with it. While endometrial hyperplasia and endometrial cancer occur most commonly among post-menopausal women, most patients with endometrial cancer have abnormal bleeding, and thus the diagnosis must be considered in women during the reproductive years. Coagulopathies (blood clotting disorders): Heavy menstrual bleeding can be related to coagulopathies. Von Willebrand disease is the most common coagulopathy, and most women with von Willebrand disease have heavy menstrual bleeding. Of women with heavy menstrual bleeding, up to 20% will have a bleeding disorder. Heavy menstrual bleeding since menarche is a common symptom for women with bleeding disorders, and in retrospective studies, bleeding disorders have been found in up to 62% of adolescents with heavy menstrual bleeding. Ovulatory dysfunction: Ovulatory dysfunction or anovulation is a common cause of abnormal bleeding that may lead to irregular and unpredictable bleeding, as well as variations in the amount of flow including heavy bleeding. Endocrine, or hormonal, causes of ovulatory disorders include polycystic ovary syndrome (PCOS), thyroid disorders, hyperprolactinemia, obesity, eating disorders including anorexia nervosa or bulimia,  or to an imbalance between exercise and caloric intake.