Abnormal Vaginal Bleeding: Causes, Risks & When to Seek Help

Recently, lisha Due to long-term irregular menstruation, a 27-year-old woman mistook vaginal bleeding that lasted for many days as normal menstruation. She did not seek medical treatment until she suddenly suffered severe tear pain in her lower abdomen. Upon examination, the doctor found an abnormal mass in his right ovary, which was confirmed to be ovarian rupture. It was further discovered during the operation that its pelvic blood volume reached 200 ml and that the ectopic embryo was in a precarious condition due to the tight adhesion between it and the ovarian blood vessels.

Ovarian pregnancy has a very low probability, but it is characterized by rapid bleeding and high risk after rupture. In clinical practice, many patients, like this woman, misidentify abdominal pain caused by ectopic pregnancy as gastroenteritis and dysmenorrhea. By the time they seek medical treatment, they often lose more blood 1500ml, almost one-third of the blood in the body was lost. This case clearly reveals the clinical importance of differential diagnosis of abnormal vaginal bleeding versus normal menstruation, and also highlights the urgency of reproductive health education for women of childbearing age.

Criteria for defining physiological menstruation and abnormal bleeding

The maintenance of a normal menstrual cycle is dependent on the hypothalamus -Precise regulation of the pituitary-ovarian axis (HPO axis), whose physiological processes involve a complete chain of follicle development, ovulation, corpus luteum formation and periodic changes in the endometrium. According to the standardized definition of “Obstetrics and Gynecology (9th Edition)”, Normal menstruation has the following characteristics: the cycle frequency is 21-35 days (coefficient of variation <7 days), menstrual length 2-8 days, menstrual volume 20-60ml (more than 80ml is defined as menorrhagia) [1] . Menstrual blood contains prostaglandins and plasmin, the latter of which prevents blood clotting, so normal menstrual blood is mostly dark red and non-clotting, and only blood clots appear when the amount of bleeding is large or fast.

Abnormal uterine bleeding ( AUB) is the most common symptom group in gynecology. In 2011, the International Federation of Obstetrics and Gynecology (FIGO) established a standardized classification system (PALM-COEIN system) ), classifying its etiology into structural abnormalities ( P: Endometrial polyps; A: Adenomyopathy; L: Uterine fibroids; M: Malignant tumors and precancerous lesions) and non-structural abnormalities (C: Coagulation dysfunction; O: Ovulation disorder; E: Endometrium Local abnormalities; I: Iatrogenic factors; N: Uncategorized). This classification system is more valuable for clinical guidance than traditional nomenclature, and has been adopted by my country’s “Guidelines for Diagnosis and Treatment of Abnormal Uterine Bleeding (2022 Update)” [2] .

The central problem for the patient in this case is the right “irregular menstruation” cognitive bias. Clinical data show that ovulation disorder type AUB (AUB-O) accounts for about 55% – 70% of AUB in women of childbearing age, and its typical manifestations are cycle disturbances (>35 days or <21 days) and periods of varying length (<2 days or >8 days), which contrast with the cyclical, self-limiting characteristics of normal menstruation. This long-term cycle abnormality led to a decrease in the patient’s vigilance regarding vaginal bleeding, ultimately delaying the diagnosis of ectopic pregnancy.

Analysis of the etiology of life-threatening abnormal bleeding

(1) Clinical characteristics and identification difficulties of ectopic pregnancy

Ectopic pregnancy ( EP) is a common acute abdomen in obstetrics and gynecology. Its incidence rate is about 2%, but it accounts for 9%-13% of early pregnancy-related deaths. Fallopian tube pregnancy accounts for about 95% of EP, with ampullary pregnancy being the most common (78%), which is related to the anatomical characteristics of the fallopian tube mucosal fold and the speed at which the fertilized egg runs.》 The Guidelines for the Diagnosis and Treatment of Ectopic Pregnancy (2023 Edition) state that The typical triad of EP is menopause, abdominal pain, and vaginal bleeding , but ca 25% of patients had no obvious history of menopause, which was highly consistent with the condition of this patient [3] .

Vaginal bleeding in fallopian tube pregnancy is mostly irregular spotting, dark red or dark brown in color, and small in amount ( <Menstrual volume) is caused by the decrease in HCG levels and endometrial dissection after embryonic death. It is easily confused with AUB-O in clinical practice. Its lethality lies in the massive intra-abdominal hemorrhage caused by the rupture of the fallopian tubes, which can present with symptoms of hemorrhagic shock such as pale complexion, fast and thin pulse, and decreased blood pressure when the amount of bleeding reaches more than 1000 ml. In ultrasound “Fallopian tube circumferential signs ” (intrafallopian tube gestational sac echo) and abdominal free fluid are important diagnostic basis. Dynamic monitoring of serum HCG (48-hour increase <53%) can be distinguished from intrauterine pregnancy.

(2) Other high-risk etiology clinical characteristics with Diagnostic points

1. Trophoblastic diseases: including hydatidiform mole, aggressive hydatidiform mole, etc., mostly manifested as abnormal vaginal bleeding after menopause, serum It is characterized by abnormally elevated HCG levels (>100,000U/L), which are detected by ultrasound “ Honeycomb ” Or “ Snowflake ” Images have diagnostic value.

2. Endometrial cancer: It is more common in perimenopausal women, mainly presenting with postmenopausal vaginal bleeding, and in nonmenopausal women it can present with increased menstrual flow, prolonged periods or irregular bleeding. The pathological examination of segmented diagnosis and curettage is the basis for diagnosis The 5-year survival rate of patients in FIGO stage Ⅰ can reach 81.6%, emphasizing the importance of early diagnosis.

3. Ovarian endocrine dysfunction: including anovulatory dysfunction and ovulatory menstrual disorder, the former is more common in adolescence and perimenopause, the latter is common in women of childbearing age, basal body temperature measurement ( BBT) can be identified (BBT single-phase in anovulatory patients, biphasic in ovulatory patients).

Normalized differential diagnostic pathways

(1) Essentials of initial evaluation

According to FIGO recommendation process, initial assessment of patients with abnormal vaginal bleeding should include [4] :

①Collection of detailed medical history (bleeding patterns, last menstrual period, sexual life history, etc.);

②General and gynecological examination (pay attention to signs such as cervical lifting pain and adnexal mass);

③Basic examination (urinary HCG, blood routine, coagulation function). For those with a history of sexual life, urine HCG testing should be used as a routine item, and its sensitivity can reach 97%, which can quickly rule out pregnancy-related diseases.

(2) Imaging and laboratory diagnostics

Transvaginal ultrasound ( TVS) is the imaging of choice Examination, which can clearly show the thickness of the endometrium (postmenopausal) >5mm requires vigilance against lesions), intrauterine space occupation (polyps, fibroids) and accessory conditions. For those with abnormal ultrasound, further hysteroscopy or diagnostic curettage is required, in which the diagnostic accuracy of hysteroscopic biopsy reaches 94%-98%, which is significantly higher than blind curettage (65%-75%).

Serum marker detection has important auxiliary value:

①HCG combined with progesterone measurement can improve EP diagnostic efficiency (progesterone <5ng/ml indicates abnormal pregnancy);

②CA125 is often elevated in patients with adenomyosis;

③Thyroid function test can rule out abnormal menstruation caused by hyperthyroidism/hypothyroidism.

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