Abnormal uterine bleeding
Abnormal uterine bleeding (AUB), also known as dysfunctional uterine bleeding, is vaginal bleeding from the uterus that is abnormally frequent, last excessively long, is more than normal, or is irregular.[1][3] Vaginal bleeding during pregnancy is excluded.[3] Iron deficiency anemia may occur and quality of life may be negatively affected.[2]
| Abnormal uterine bleeding | |
|---|---|
| Other names | Dysfunctional uterine bleeding (DUB), abnormal vaginal bleeding |
| Specialty | Gynecology |
| Symptoms | Irregular, abnormally frequent, prolonged, or excessive amounts of uterine bleeding[1] |
| Complications | Iron deficiency anemia[2] |
| Causes | Ovulation problems, fibroids, lining of the uterus growing into the uterine wall, uterine polyps, underlying bleeding problems, side effects from birth control, cancer[3] |
| Diagnostic method | Based on symptoms, blood work, medical imaging, hysteroscopy[2] |
| Differential diagnosis | Ectopic pregnancy[4] |
| Treatment | Hormonal birth control, GnRH agonists, tranexamic acid, NSAIDs, surgery[1][5] |
| Frequency | Relatively common[2] |
The underlying causes may include ovulation problems, fibroids, the lining of the uterus growing into the uterine wall, uterine polyps, underlying bleeding problems, side effects from birth control, or cancer.[3] More than one category of causes may apply in an individual case.[3] The first step in work-up is to rule out a tumor or pregnancy.[5][3] Medical imaging or hysteroscopy may help with the diagnosis.[2]
Treatment depends on the underlying cause.[3][2] Options may include hormonal birth control, gonadotropin-releasing hormone (GnRH) agonists, tranexamic acid, NSAIDs, and surgery such as endometrial ablation or hysterectomy.[1][5] AUB affects about 20% of reproductive aged women.[2]
Signs and symptoms
Symptoms include vaginal bleeding that occurs irregular, at abnormal frequency, last excessively long, or is more than normal.[1] Normal frequency of periods is 22 to 38 days.[1][3] Variation in the length of time between cycles is typically less than 21 days.[3] Bleeding typically last less than 9 days and blood loss is less than 80 mL.[1][3] Excessive blood loss may also be defined as that which negatively affects a person's quality of life.[2] Bleeding more than six month after menopause is also a concern.[4]
Causes
The causes of AUB is divided into nine groups which includes: uterine polyps, fibroids, adenomyosis, cancer, blood clotting disorders, problems with ovulation, endometrial problems, healthcare induced, and not yet classified.[3] More than one category of causes may apply in an individual case.[3] Healthcare induced causes may include side effects of birth control.[3]
Mechanism
The underlying mechanism is often a hormonal disturbances: reduced levels of progesterone cause high levels of prostaglandin F2-alpha and cause abnormally heavy flow as progesterone stabilizes the endometrium and inhibits synthesis of prostaglandin F2-alpha; increased levels of tissue plasminogen activator (t-PA), a fibrinolytic enzyme, lead to more fibrinolysis.
Ovulatory
10% of cases occur in women who are ovulating, but progesterone secretion is prolonged because estrogen levels are low. This causes irregular shedding of the uterine lining and break-through bleeding. Some evidence has associated Ovulatory DUB with more fragile blood vessels in the uterus.
It may represent a possible endocrine dysfunction, resulting in menorrhagia or metrorrhagia. Mid-cycle bleeding may indicate a transient estrogen decline, while late-cycle bleeding may indicate progesterone deficiency.
Anovulatory
About 90% of DUB events occur when ovulation is not occurring (Anovulatory DUB). Anovulatory menstrual cycles are common at the extremes of reproductive age, such as early puberty and perimenopause (period around menopause). In such cases, women do not properly develop and release a mature egg. When this happens, the corpus luteum, which is a mound of tissue that produces progesterone, does not form. As a result, estrogen is produced continuously, causing an overgrowth of the uterus lining. The period is delayed in such cases, and when it occurs menstruation can be very heavy and prolonged. Sometimes anovulatory DUB is due to a delay in the full maturation of the reproductive system in teenagers. Usually, however, the mechanisms are unknown.
The cause can be psychological stress, weight (obesity, anorexia, or a rapid change), exercise, endocrinopathy, neoplasm, drugs, or it may be otherwise unknown.
Diagnosis
Diagnosis of DUB starts with a medical history and physical examination.[2] Testing the hemoglobin level and doing a pelvic ultrasound is often done.[2] Ultrasound is specifically recommended in those over the age of 35 or in who bleeding continues despite initial treatment.[4]
Laboratory assessment of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, T4, thyroid stimulating hormone (TSH), pregnancy (by βhCG), and androgen profile should also happen.
More extensive testing might include an MRI and endometrial sampling.[2] Endometrial sampling is recommended in those over the age of 45 who do not improved with treatment and in those with intermenstrual bleeding that persists.[2]
Management
Treatment depends on the underlying cause.[3][2] Options may include hormonal birth control, gonadotropin-releasing hormone (GnRH) agonists, tranexamic acid, NSAIDs, and surgery such as endometrial ablation or hysterectomy.[1][5] Polyps, adenomyosis, and cancer are generally treated by surgery.[2] Iron supplementation may be needed.[2]
Terminology
The terminology "dysfunctional uterine bleeding" is no longer recommended.[3] Historically dysfunctional uterine bleeding meant there was no structural or systemic problems present.[3] In AUB underlying causes may be present.[3]
References
- "Abnormal Uterine Bleeding". ACOG. March 2017. Retrieved 11 September 2018.
- Whitaker L, Critchley HO (July 2016). "Abnormal uterine bleeding". Best Pract Res Clin Obstet Gynaecol. 34: 54–65. doi:10.1016/j.bpobgyn.2015.11.012. PMC 4970656. PMID 26803558.
- Bacon, JL (June 2017). "Abnormal Uterine Bleeding: Current Classification and Clinical Management". Obstetrics and Gynecology Clinics of North America. 44 (2): 179–193. doi:10.1016/j.ogc.2017.02.012. PMID 28499529.
- "Vaginal Bleeding". Merck Manuals Professional Edition. Retrieved 11 September 2018.
- Cheong, Y; Cameron, IT; Critchley, HOD (1 September 2017). "Abnormal uterine bleeding". British Medical Bulletin. 123 (1): 103–114. doi:10.1093/bmb/ldx027. PMID 28910998.