Abnormal Uterine Bleeding Time Period Definition
Abnormal uterine bleeding (AUB) is defined as bleeding from the uterus that is abnormal in regularity, volume, frequency, or duration, with normal menstrual periods lasting 3-6 days and involving blood loss of up to 80ml. 1, 2
Normal vs. Abnormal Menstrual Parameters
- Normal menstrual periods last 3-6 days and involve blood loss of up to 80ml 2
- Menorrhagia (heavy menstrual bleeding) is defined as menstrual periods lasting more than 7 days and/or involving blood loss greater than 80ml 2
- AUB encompasses heavy menstrual bleeding, irregular menstrual bleeding, and intermenstrual bleeding in women of reproductive age 3
Classification of Abnormal Uterine Bleeding
- The International Federation of Gynecology and Obstetrics (FIGO) developed the PALM-COEIN classification system to describe uterine bleeding abnormalities in women of reproductive age 4, 1
- Structural causes (PALM) include polyps, adenomyosis, leiomyoma (submucosal or other myoma), and malignancy/hyperplasia 4, 1
- Nonstructural causes (COEIN) include coagulopathy, ovulatory dysfunction, endometrial disorders, iatrogenic causes, and not yet classified conditions 4, 1
Specific Abnormal Bleeding Patterns
- Heavy menstrual bleeding (HMB): Ovulatory bleeding exceeding 8 days duration 5
- Intermenstrual bleeding (IMB): Bleeding that occurs between regular menstrual periods 5
- Anovulatory bleeding: Irregular bleeding pattern often associated with conditions like polycystic ovary syndrome, uncontrolled diabetes mellitus, thyroid dysfunction, or hyperprolactinemia 6
Age-Specific Considerations
- Reproductive-age women: AUB prevalence is estimated at 11-13% in the general population and increases with age, reaching 24% in those aged 36-40 years 2
- Perimenopausal women: Often experience AUB due to anovulation, but structural causes must be ruled out 1
- Postmenopausal women: Any bleeding is abnormal and requires evaluation for endometrial cancer 1
Common Pitfalls and Caveats
- Failure to distinguish between structural and non-structural causes can lead to inappropriate management 4, 1
- Not all abnormal bleeding is due to uterine pathology; cervical or vaginal sources must be ruled out through proper examination 2
- Pregnancy must always be excluded when evaluating AUB through appropriate testing 2
- Transvaginal ultrasonography is not typically recommended in virgins; transabdominal imaging may be used instead, though it has lower sensitivity 4
Clinical Implications
- Women with recurrent anovulation (especially those 35 years or older) or with risk factors for endometrial cancer should undergo endometrial biopsy 6
- When medical treatment fails, further investigation with imaging or hysteroscopy is indicated 4
- Treatment options range from medical (hormonal contraceptives, progestins, tranexamic acid) to surgical interventions (endometrial ablation, hysterectomy) depending on the underlying cause 4, 7