The medical abbreviation DUB stands for Dysfunctional Uterine Bleeding, a term historically used to describe irregular bleeding from the uterus. The bleeding is considered “dysfunctional” because it occurs outside the normal menstrual cycle parameters of frequency, regularity, duration, or volume. DUB was a diagnosis of exclusion, applied when no other structural, systemic, or pregnancy-related cause could be identified. The primary driver of this type of bleeding was hormonal imbalance.
Dysfunctional Uterine Bleeding Defined
Dysfunctional Uterine Bleeding historically referred to abnormal bleeding resulting specifically from hormonal disruptions, such as a lack of regular ovulation. The bleeding was not caused by structural problems like fibroids or polyps, nor by systemic diseases or medications. The condition arose from an imbalance between estrogen and progesterone, which control the buildup and shedding of the uterine lining. This hormonal issue is most common in adolescents and in women approaching menopause.
The medical community has largely replaced the older term DUB with Abnormal Uterine Bleeding (AUB). AUB is a broader, standardized term that covers all bleeding deviating from the normal menstrual pattern. The original concept of DUB is now captured within the AUB subcategories related to ovulatory dysfunction (AUB-O) or primary endometrial issues (AUB-E). Adopting AUB terminology allows doctors to systematically classify the underlying cause.
Clinical Characteristics of Abnormal Bleeding
Abnormal Uterine Bleeding is characterized by changes in four aspects of menstruation: frequency, duration, volume, and regularity. A cycle is too frequent if the interval is less than 24 days, or too infrequent if it occurs less often than every 38 days. Duration is prolonged if a period lasts longer than eight days. Volume is described as heavy menstrual bleeding, often defined subjectively as soaking through one or more sanitary products every hour for several consecutive hours, or objectively as blood loss exceeding 80 milliliters per cycle. Bleeding that occurs unexpectedly between menstrual periods, known as intermenstrual bleeding or spotting, is also a common characteristic of AUB.
Identifying the Source (The PALM-COEIN Framework)
To move beyond the vague diagnosis of DUB, the medical community uses the PALM-COEIN classification system to identify the precise source of Abnormal Uterine Bleeding. This framework divides potential causes into two main groups: structural and non-structural. The PALM acronym represents the structural causes, which are identified visually, often through imaging like ultrasound or hysteroscopy.
The structural causes are represented by PALM. Polyp (AUB-P) refers to growths on the inner lining of the uterus, and Adenomyosis (AUB-A) is where endometrial tissue grows into the muscular wall of the uterus. Leiomyoma (AUB-L) refers to uterine fibroids, which are benign muscle tumors. Malignancy and hyperplasia (AUB-M) refers to cancer or precancerous changes in the uterine lining. These structural issues can physically disrupt the uterus’s ability to control bleeding.
The COEIN acronym represents the non-structural or systemic causes, typically identified through laboratory tests or patient history. Coagulopathy (AUB-C) refers to systemic bleeding disorders that impair the body’s ability to clot blood effectively. Ovulatory dysfunction (AUB-O) covers hormonal imbalances, such as those seen in polycystic ovary syndrome (PCOS), which was the original definition of DUB. Endometrial disorders (AUB-E) are primary problems with the uterine lining causing heavy bleeding. Iatrogenic (AUB-I) causes are triggered by medical interventions, such as certain medications. Not yet classified (AUB-N) is reserved for rare conditions that do not fit into the other categories. This systematic approach ensures that treatment is directly targeted at the correct underlying cause.
Management and Treatment Approaches
Treatment for Abnormal Uterine Bleeding depends entirely on the specific PALM-COEIN diagnosis and the patient’s desire for future fertility. The immediate goal is often to control acute, heavy bleeding, sometimes requiring high-dose intravenous estrogen or oral hormonal regimens to stabilize the uterine lining. For less severe or chronic bleeding, a targeted long-term strategy is implemented.
If the cause is non-structural, such as ovulatory dysfunction (AUB-O), hormonal therapies are the standard approach. These treatments often include combined oral contraceptives, progestin-only pills, or a levonorgestrel-releasing intrauterine device (LNG-IUD). Non-hormonal options, such as tranexamic acid, can also be used to reduce blood loss by promoting blood clotting within the uterus.
For structural causes identified by the PALM categories, surgical intervention is frequently necessary. Polyps are often removed through a minimally invasive procedure called hysteroscopic polypectomy. Large or symptomatic fibroids may require a myomectomy, which removes the fibroids while preserving the uterus. If medical and less invasive surgical options have failed, or for patients who have completed childbearing, a hysterectomy (removal of the uterus) may be considered as a definitive treatment.