Dysfunctional Uterine Bleeding (DUB): This is the most common cause of abnormal vaginal bleeding in women of reproductive age, often related to hormonal imbalances affecting the normal menstrual cycle.

Uterine Fibroids: These are common benign tumors that can cause prolonged or heavy menstrual bleeding due to their location and effect on the uterine lining.
Endometrial Hyperplasia: A condition where the lining of the uterus grows too thick, which can lead to prolonged and heavy bleeding, often associated with anovulatory cycles.
Hormonal Contraceptive-Related Bleeding: Changes in bleeding patterns are common when starting, stopping, or changing hormonal contraceptives, which can lead to prolonged bleeding.

Endometrial Cancer: Although less common, it is crucial to rule out endometrial cancer, especially in postmenopausal women or those with risk factors like obesity, diabetes, or a family history of gynecologic cancers.
Cervical Cancer: Prolonged vaginal bleeding can be a symptom of cervical cancer, making it essential for screening and diagnosis.
Pregnancy-Related Complications: Ectopic pregnancy or a molar pregnancy can present with abnormal vaginal bleeding and are medical emergencies.

Bleeding Disorders (e.g., von Willebrand Disease): These can cause heavy or prolonged menstrual bleeding due to difficulties in blood clotting.
Uterine Arteriovenous Malformations (AVMs): Rare vascular anomalies that can cause abnormal uterine bleeding.
Systemic Diseases (e.g., Thyroid Disorders, Coagulopathies): Certain systemic conditions can affect menstrual regularity and bleeding, though they are less common causes of prolonged vaginal bleeding.