What are the causes of abnormal uterine bleeding (AUB)?

From the Guidelines

Irregular menstrual bleeding should be evaluated by a healthcare provider, especially if it's new, severe, or accompanied by other symptoms, and the most appropriate initial imaging study is combined transabdominal and transvaginal ultrasound of the pelvis with Doppler, as recommended by the American College of Radiology Appropriateness Criteria 1. The evaluation of irregular menstrual bleeding involves a thorough history, physical examination, and appropriate laboratory tests, and may include imaging to assess for structural abnormalities, such as endometrial polyps, adenomyosis, leiomyoma, malignancy, and endometrial hyperplasia 1. Common causes of irregular menstrual bleeding include:

• Structural causes, such as polyps, adenomyosis, and leiomyoma, which are common in premenopausal women 1
• Nonstructural causes, such as coagulopathies, ovulatory dysfunction, primary endometrial disorders, iatrogenic etiologies, and other causes not otherwise classified 1 Treatment options for irregular menstrual bleeding include:
• Hormonal contraceptives, such as combined oral contraceptives, which can be taken continuously or cyclically to regulate bleeding 1
• Tranexamic acid or NSAIDs, such as ibuprofen, to reduce heavy bleeding [@Example@]
• Iron supplementation, such as ferrous sulfate, to treat anemia [@Example@]
• Lifestyle modifications, such as maintaining a healthy weight, managing stress, and regular exercise, to help regulate menstrual cycles [@Example@] It is essential to seek immediate medical attention for extremely heavy bleeding, severe pain, fever, or if pregnant, and to track bleeding patterns using a calendar or app to help the healthcare provider make an accurate diagnosis and recommend appropriate treatment [@Example@].

From the FDA Drug Label

Breakthrough bleeding, spotting, and amenorrhea are frequent reasons for patients discontinuing oral contraceptives. In breakthrough bleeding, as in all cases of irregular bleeding from the vagina, non-functional causes should be borne in mind In undiagnosed persistent or recurrent abnormal bleeding from the vagina, adequate diagnostic measures are indicated to rule out pregnancy or malignancy. If pathology has been excluded, time or a change to another formulation may solve the problem. Breakthrough bleeding and spotting are sometimes encountered in patients on oral contraceptives, especially during the first three months of use Non-hormonal causes should be considered and adequate diagnostic measures taken to rule out malignancy or pregnancy in the event of breakthrough bleeding, as in the case of any abnormal vaginal bleeding.

Irregular menstrual bleeding can be caused by the use of oral contraceptives, such as ethinyl estradiol.

• Breakthrough bleeding and spotting are common side effects, especially during the first three months of use.
• Adequate diagnostic measures should be taken to rule out malignancy or pregnancy in the event of abnormal vaginal bleeding.
• If pathology has been excluded, time or a change to another formulation may solve the problem 2, 2.

From the Research

Causes and Classification of Irregular Menstrual Bleeding

• Irregular menstrual bleeding can be caused by various factors, including uterine abnormalities, hormonal imbalances, and the use of intrauterine devices (IUDs) 3.
• The PALM-COEIN system is used to classify the etiologies of acute abnormal uterine bleeding, which helps in determining the appropriate treatment approach 4.

Treatment Options for Irregular Menstrual Bleeding

• Medical management is the initial treatment for most patients with irregular menstrual bleeding, and options include intravenous conjugated equine estrogen, combined oral contraceptives, oral progestins, and tranexamic acid 4.
• Non-steroidal anti-inflammatory drugs (NSAIDs) can reduce menstrual blood loss by 20-60% and are often used to treat heavy menstrual bleeding 5, 6, 7.
• The levonorgestrel-releasing intrauterine system (LNG IUS) is also an effective treatment option for heavy menstrual bleeding, with a comparable effectiveness to endometrial ablation or hysterectomy 5.

Management of Heavy Menstrual Bleeding Associated with IUD Use

• Heavy menstrual bleeding and pain are common reasons for discontinuing IUD use, with copper IUD users tend to experience increased menstrual bleeding and levonorgestrel IUD users tend to have irregular menstruation 3.
• Medical therapies such as NSAIDs, anti-fibrinolytics, and paracetamol can be used to reduce heavy menstrual bleeding or pain associated with IUD use 3.
• Vitamin B1 and mefenamic acid may be effective in treating heavy menstruation associated with copper IUD use, while tolfenamic acid may prevent heavy bleeding 3.

Diagnosis and Assessment of Irregular Menstrual Bleeding

• A thorough assessment of the patient's medical history and a pelvic examination are essential in diagnosing and managing irregular menstrual bleeding 4, 5.
• Vaginal sonography and endometrial biopsy can be used to diagnose endometrial hyperplasia or carcinoma, while sonohysterography or hysteroscopy can diagnose endometrial polyps and fibroids 5.