Abnormal uterine bleeding (AUB) is a common gynecologic sign and symptom that refers to abnormal bleeding from the uterine cavity that is inconsistent with any of the normal menstrual cycle frequency, regularity, length of periods, or volume of menstrual bleeding. The AUB described in this guideline is limited to non-pregnant women of childbearing age and therefore excludes bleeding associated with pregnancy and the puerperium, as well as prepubertal and postmenopausal bleeding. I. Terminology update 1. Normal uterine bleeding is menstruation, and the standardized menstrual indicators include at least four elements: frequency and regularity of the cycle, length of the period, and the amount of menstrual bleeding. Our tentative terminology standards are as follows, other should also have menstrual discomfort, such as dysmenorrhea, lumbar acidity, falling, etc. 2. Abolition of terms: Abolition of “menstrual bleeding” and metrorrhagia (uterine bleeding), menorrhagia (excessive menstruation) and other terms with Greek or Latin roots. (3) Retained terms: (1) intermenstrual bleeding; (2) irregular uterine bleeding; (3) breakthrough bleeding: bleeding in the case of heavy bleeding and spotting in the case of small amount of bleeding. (2) Acute AUB: refers to AUB with severe hemorrhage that the physician believes requires urgent treatment to prevent further blood loss, and can be seen in patients with or without a history of chronic AUB. 1. For patients with AUB (i.e., menstrual disorders), the first step is to confirm the specific bleeding pattern by detailed questioning of the history of menstrual changes, i.e., the patient’s chief complaint. The flow is shown in Figure 1. 2 .Diagnosis of frequent menstruation, excessive menstruation, prolonged menstruation, and irregular menstruation: The flow is shown in Figure 2. 3 .Menorrhagia: It is 1 bleeding pattern of AUB and is common in clinical practice. Its etiology can be due to insufficient ovarian estrogen secretion, anovulation or endometrial non-response to normal amounts of hormones due to surgical trauma, inflammation, adhesions, etc. See Figure 3 for the consultation and management process.4, Scanty menstruation: See Figure 4 for the consultation and management process.5, Intermenstrual bleeding (IMB): This refers to regular bleeding that occurs between expected menstrual periods. It can be classified as follicular bleeding, periovulatory bleeding and luteal bleeding according to the timing of bleeding. The diagnostic process is shown in Figure 5. 1. Clinically, 70%-90% of endometrial polyps have AUB, which manifests as intermenstrual bleeding, excessive menstruation, irregular bleeding and infertility. Usually, they can be detected by pelvic ultrasound, and the best time for examination is before the 10th day of the cycle; the diagnosis should be confirmed by hysteroscopic removal and pathological examination. 2, Treatment of AUB due to endometrial polyps: ① polyps <1 cm in diameter can be observed and followed up if they are asymptomatic. ②For larger polyps with symptoms, hysteroscopic removal of polyps and scraping is recommended, blind scraping is easy to miss. ③For those who have completed childbirth or do not want to have children in the near future, short-acting oral contraceptives or levonorgestrel intrauterine delayed release system (LNG-IUS) can be considered to reduce the risk of recurrence. Endometrial resection may be recommended for those who do not require childbearing and have multiple recurrences. Hysterectomy may be considered for those with high risk of malignancy. The diagnosis of AUB due to adenomyosis requires pathological examination, and the initial diagnosis can be made clinically on the basis of typical symptoms and signs and increased blood CA125 level. Ultrasound examination of pelvis can assist in diagnosis, and MRI examination is feasible if available. 4. Treatment of AUB-A: ①For those with mild symptoms, short-acting oral contraceptives and gonadotropin-releasing hormone agonists (GnRH-a) can be used for 3-6 months. (2) LNG-IUS can also be placed for those who have no recent fertility requirements and whose uterus size is smaller than 8 weeks of gestation; for those whose uterus size is larger than 8 weeks of gestation, the combination of GnRH-a and LNG-IUS can be considered. ③Total hysterectomy is feasible for those who do not have fertility requirements, have severe symptoms, are old, or have failed drug treatment. ④Patients with fertility requirements and adenomyoma may consider local lesion excision + GnRH-a treatment followed by assisted reproductive technology treatment. 5.AUB due to uterine smooth muscle tumor: For women with predominantly heavy menstruation who have completed childbirth, short-acting oral contraceptives and LNG-IUS can relieve the symptoms. Women with fertility requirements can be treated with GnRH-a and mifepristone for 3-6 months, and pregnancy can be considered after the symptoms improve. In severe cases, hysteroscopy, laparoscopy or open myomectomy may be performed. 6. Atypical endometrial hyperplasia and malignancy are rare but important causes of AUB. Endometrial biopsy and pathological examination are required for definite diagnosis. 7. AUB due to endometrial malignancy and atypical hyperplasia: (1) Hysterectomy is recommended for patients >40 years of age without fertility requirements. (2) For young patients with fertility requirements, after comprehensive evaluation and adequate consultation, endometrial atrophy can be treated with a full cycle of continuous high efficiency synthetic progestin, such as methylhydroxyprogesterone and megestrol, and 3-6 months later, diagnostic scraping plus uterine aspiration (for the purpose of comprehensive extraction) can be performed. 8. Systemic coagulation abnormalities such as aplastic anemia, various types of leukemia, various coagulation factor abnormalities, and thrombocytopenia from various causes can also lead to AUB. 9. Patients with positive results for any one of the following three items suggest possible coagulation abnormalities and should consult a hematologist, including: (1) excessive menstrual flow from menarche; (2) a history of one of the following: previous postpartum, post-surgical, or dental (3) Two or more of the following symptoms: bruising 1-2 times per month, nosebleeds 1-2 times per month, frequent gum bleeding, family history of bleeding tendency. 10. Missed doses of contraceptive pills can cause withdrawal bleeding. Prolonged menstruation due to IUD insertion may be related to excessive local prostaglandin production or hyperfibrinolysis; BTB also occurs frequently within 6 months in women who have first applied LNG-IUS or subcutaneous implants; use of rifampin, anticonvulsants, and antibiotics also predispose to the development of AUB-I.