Hematometra: Why does blood accumulate in the uterus and what to do?

Hematometra is a collection of blood in the uterine cavity due to impaired outflow through the cervical canal or due to intracavitary obstruction. The condition may develop acutely with severe pain and pressure in the lower abdomen or gradually, manifesting as episodes of spotting, secondary amenorrhea, and discomfort. Without prompt treatment, infection of the contents and systemic symptoms are possible. Therefore, hematometra is a condition requiring prompt diagnosis and targeted treatment. [1]

Classic causes include cervical stenosis after surgical interventions, intrauterine adhesions in Asherman syndrome, obstructive malformations, and complications after endometrial treatment procedures. Less common causes include post-cesarean section scar defects, where blood accumulates in the scar niche and forms a localized hematometra. Understanding these mechanisms guides the clinician in choosing treatment strategies. [2]

Diagnosis is typically established by transvaginal ultrasound, which visualizes a dilated uterine cavity with echogenic or anechoic contents. In complex cases, magnetic resonance imaging is used to clarify the anatomy and detect intrauterine septa or scar defects. Once the diagnosis is confirmed, the primary goal is safe evacuation of the contents and elimination of the cause of the obstruction. [3]

A multidisciplinary approach, including a gynecologist, a radiologist, and, if necessary, a reproductive specialist, not only relieves acute pain but also prevents recurrences and reproductive complications. Individualized treatment is especially important for patients planning pregnancy. [4]

Epidemiology

Hematometra occurs in various age groups, but is most often diagnosed in women of reproductive age after intrauterine interventions, in perimenopause due to cervical stenosis, and in patients with obstructive developmental anomalies. The exact incidence is unknown due to the heterogeneity of causes and the lack of population-based studies. However, clinical series describe regular findings of hematometra in patients after endometrial ablation or cervical reconstructive surgery. [5]

Following endometrial ablation, a wide range of obstructive complications is possible, including cornual hematometra and so-called post-ablation pain syndrome. Retrospective observations indicate that such complications may occur with a delay and require vigilance for the development of secondary amenorrhea and pain. [6]

In adolescents and young women, hematometra is most often associated with obstructive Müllerian anomalies. In these situations, blood accumulation is often associated with hematocolpos and hematosalpinx, and temporary puncture relief may be used as a bridge to definitive reconstruction. [7]

The condition has also been described in patients after cesarean section, where a localized blood collection forms in the scar niche. Modern ultrasound and magnetic resonance imaging help recognize this condition and plan treatment, emphasizing the role of experienced radiology. [8]

Reasons

The leading causes of hematometra can be divided into two broad groups: cervical outflow obstructions and intrauterine obstructions. The first group includes cervical stenosis following procedures, destruction, or coagulation, postpartum, and perimenopause. The second group includes intrauterine adhesions associated with Asherman's syndrome, septa, dense polyps, or the consequences of ablation. Each mechanism impairs menstrual blood flow in its own way. [9]

Asherman's syndrome is a common cause of intrauterine obstruction. It develops as a result of trauma to the functional layer of the endometrium, most often following curettage of the uterine cavity due to pregnancy or infectious complications. There is no conservative alternative to surgical dissection of adhesions, which determines the central role of hysteroscopy in treatment. [10]

Obstructive Müllerian anomalies, such as Robert's septum or non-communicating cavities, lead to blood accumulation in an isolated horn or segment of the uterus. Magnetic resonance imaging allows visualization of the septum and assessment of the degree of obstruction, which is critical for choosing a reconstructive strategy. [11]

A rare but clinically significant cause is a defect in the cesarean section scar, where a localized cavity containing stagnant fluid forms. This type of hematometra is corrected using targeted methods, ranging from medication to surgical reconstruction of the defect. [12]

Risk factors

Risk factors include recent intrauterine interventions, endometrial ablation, dilation and curettage, cervical reconstructive surgery, frequent infections, and chronic endometritis. In perimenopause, age-related narrowing of the cervical canal plays a role. The combination of these factors increases the likelihood of outflow obstruction and subsequent blood retention. [13]

For patients planning reproductive health, additional risks are associated with the formation of adhesions following complicated abortions or retained products of conception. Early rehabilitation of the uterine cavity and gentle techniques reduce the likelihood of severe adhesions. [14]

Among developmental anomalies, non-communicating cavities, septa, and atresias pose a risk for hematometra. This category requires early recognition, as prolonged retention causes pain, inflammation, and endometriosis due to retrograde reflux. [15]

After cesarean section, the risk of local hematometra increases with a pronounced scar defect, thin myometrium in the niche area, and unfavorable scar architecture. Visualization and risk stratification guide the choice between conservative and surgical approaches. [16]

Table 1. Main causes and risk factors of hematometra

Group of reasons	Specific examples	Associated risk factors
Obstruction of outflow through the cervix	Cervical stenosis, cicatricial changes	Age, cervical surgery, destruction
Intrauterine obstructions	Adhesions in Asherman's syndrome, septa, dense polyps	Curettage, infection, endometrial trauma
After endometrial ablation	Cornual retention, post-ablation syndrome	Prior tubal sterilization, deep ablation
Post-cesarean scar defect	Scar niche with blood retention	Repeated operations, thin myometrium

Pathogenesis

The key mechanism of hematometra is mechanical obstruction of the outflow tract. With cervical stenosis, even a small amount of blood cannot be evacuated in a timely manner, distending the uterine cavity and causing pain. This distension causes ischemia and increased pain impulses, creating a vicious cycle of pain and spasm. [17]

In intrauterine adhesions, the cavity is divided into chambers that communicate imperfectly or not at all. As a result, blood accumulates proximal to the block, and chronic stagnation promotes inflammation and secondary scarring. This explains the tendency for recurrence with incomplete dissection of adhesions. [18]

Following endometrial ablation, focal mucosal destruction may be accompanied by preserved areas of the endometrium that continue to bleed in a confined space. Corneal retention, where blood collects in the area of the fallopian tube orifices, is particularly common. In such cases, standard cervical dilation provides only temporary relief. [19]

A defective cesarean section scar results in the formation of a localized cavity in the scar area. The rough internal surface and altered myometrial peristalsis impair drainage, and the re-accumulation of blood maintains chronic inflammation and pain. Topical reconstruction addresses the underlying cause. [20]

Symptoms

The most common symptoms are cyclical or constant lower abdominal pain, a feeling of distension, secondary amenorrhea, or a significant decrease in menstrual flow, sometimes with spotting. Palpation may reveal an enlarged, tender uterus. A significant warning sign is increasing pain with no menstrual blood flow. [21]

If the contents become infected, fever, weakness, nausea, and pain during urination or defecation occur. This condition requires immediate evaluation and a combination of drainage and antibiotic therapy. Delayed treatment increases the risk of generalized infection. [22]

Patients undergoing endometrial ablation typically present with a recent procedure, secondary amenorrhea, and gradually increasing pain. The pain may be unilateral with localized retention, which helps the clinician suspect a corneal variant. [23]

In developmental anomalies, early onset of symptoms after menarche is often observed, with each menstrual period accompanied by increasing pain. Ultrasound and magnetic resonance imaging help establish a connection with a specific anatomical obstruction and assess the volume of the cluster. [24]

Forms and stages

For practical purposes, acute and chronic forms are distinguished. The acute form is accompanied by severe pain and uterine enlargement and requires urgent drainage. The chronic form is characterized by recurrent pain, episodes of spotting, and a decrease in quality of life, often associated with adhesions or the consequences of ablation. [25]

Anatomically, a distinction is made between total hematometra, where blood fills the main cavity, and localized hematometra, such as corneal hematometra or a scar niche. These variants differ in their symptoms and require different technical approaches to treatment. [26]

Hematometra is considered separately in the setting of obstructive Müllerian anomalies. This is referred to as hematometrocolpus or a combination with hematosalpinx, which requires a stepwise approach: temporary anesthesia and drainage, followed by reconstruction. [27]

In clinical protocols, it is convenient to indicate the degree of severity based on the volume of retention and the presence of infection. This stratification helps plan the need for antibacterial therapy and the extent of surgical intervention. [28]

Table 2. Clinical forms of hematometra

Criterion	Options	Practical significance
Flow	Acute, chronic	Urgency of drainage, volume of assistance
Localization	Total, cornual, in the scar niche	Choice of access and technology
Etiology	Cervical stenosis, synechiae, post-ablation variant, developmental anomalies	Primary and preventive treatment plan
Complications	Without infection, with infection	The need for antibacterial therapy

Complications and consequences

The main complications of untreated hematometra include infection of the contents, endometritis, the formation of intrauterine adhesions, and chronic pain. In severe cases, infection may spread and the general condition may worsen. Early evacuation and antibacterial protection reduce these risks. [29]

With repeated retention against the background of adhesions, a vicious cycle of pain and inflammation develops, which threatens to worsen reproductive prospects. Recurrences of pain syndrome and the need for repeat interventions, including hysterectomy in refractory cases, have been described in patients after endometrial ablation. [30]

In adolescents, prolonged retention due to developmental abnormalities can lead to endometriosis due to retrograde blood flow. This further complicates the reproductive prognosis and increases pain, requiring timely correction of the anatomical defect. [31]

Psychological consequences include anxiety and decreased quality of life. Comprehensive care involving a psychologist and a detailed explanation of the diagnosis reduces emotional distress and improves treatment adherence. [32]

Table 3. Frequent complications and their prevention

Complication	How to prevent
Content contamination	Timely drainage, antibacterial therapy as indicated
Relapse due to incomplete correction	Targeted correction of the cause, control visualization
Formation of adhesions	Gentle technique, adhesion prevention, early cavity rehabilitation
Chronic pain	Complete relief of obstruction, stepwise management and observation

Diagnostics

The first step is a clinical assessment of pain, palpation to identify an enlarged, tender uterus, and exclusion of pregnancy in women of reproductive age by measuring human chorionic gonadotropin. This is important for safe planning of further steps and ruling out competing diagnoses. [33]

The basic imaging method is transvaginal ultrasound. It reveals a dilated uterine cavity with fluid contents of varying echogenicity, sometimes with levels and suspensions. This method is accessible and allows for evaluation of the cervix and indirect detection of adhesions. If the anatomy is unclear or septa and scar niches are suspected, magnetic resonance imaging is indicated. [34]

In the laboratory, a complete blood count is appropriate for severe pain and signs of inflammation, and infection markers are indicated for fever. If adhesions or structural pathology are suspected, diagnostic hysteroscopy is indicated, which combines diagnosis and treatment. Blind manipulation without visual control is undesirable due to the risk of injury. [35]

In post-ablation conditions, targeted imaging protocols assessing the horns and tubal orifice area are important, as corneal retention may be missed during a standard examination. In these situations, a combination of ultrasound and magnetic resonance imaging improves diagnostic accuracy. [36]

Table 4. Diagnostic algorithm for suspected hematometra

Step	Action	Target
1	Exclusion of pregnancy	Security and proper routing
2	Transvaginal ultrasound	Confirmation of retention, assessment of the cervix
3	Magnetic resonance imaging as indicated	Anatomy map, septum, niche
4	Diagnostic hysteroscopy	Verification and one-time correction

Differential diagnosis

Hematometra is differentiated from pregnancy, including non-viable and ectopic pregnancy, degenerative uterine myoma, pyometra, large intrauterine polyps, and fluid accumulation in cervical obstructive syndrome without active bleeding. The sequence is important: first rule out pregnancy, then consider structural causes. [37]

Hematometra is distinguished from pyometra by the absence of pronounced intoxication and the nature of the contents on ultrasound. If in doubt, diagnostic hysteroscopy and microbiological testing are the answer. Timely differentiation determines the extent of antibacterial therapy. [38]

In post-ablation pain syndrome, it is necessary to differentiate cornual hematometra from adenomyosis and other causes of chronic pain. Careful targeted scanning of the uterine horns and comparison with clinical findings improve accuracy. [39]

In adolescents, it is important to identify obstructive anomalies that may mimic dysmenorrhea. Magnetic resonance imaging and expert ultrasound examination can help avoid delays in diagnosis. [40]

Table 5. Differential diagnosis of hematometra

State	What helps to distinguish
Pregnancy and its complications	Determination of human chorionic gonadotropin, visualization of the ovum
Pyometra	Intoxication, purulent contents, bacteriological data
Myoma with degeneration	Myometrial nodular formation on visualization
Post-ablation pain syndrome without retention	Absence of cavity contents, signs of adenomyosis

Treatment

The basic principle is evacuation of the contents and elimination of the cause of the obstruction. In case of cervical stenosis, the first line is gentle dilation with aspiration of the cavity. In the presence of intrauterine adhesions, hysteroscopic dissection under visual control is preferable. Drug monotherapy without removal of the blockage is ineffective. [41]

If infection occurs, drainage is combined with empirical antibacterial therapy, followed by adjustments based on microbiological data. This reduces the risk of infection spread and accelerates recovery. The need for adhesion prophylaxis is assessed postoperatively. [42]

In post-ablation cornual hematometra, simple dilation often provides a temporary effect. Targeted interventions are considered, including resection of obstructive tissue, expansion of the cornual segment, or, in refractory cases, hysterectomy. The choice depends on the severity of pain, age, and reproductive plans. [43]

In adolescents and with developmental anomalies, temporary puncture unloading under visual control is possible as a bridge to reconstruction. This approach reduces pain, allows for planning of the final intervention, and reduces risks. Once ready, septal reconstruction and restoration of normal outflow are performed. [44]

Table 6. Comparison of treatment tactics

Situation	First line tactics	Alternatives and additions	Comments
Cervical stenosis without adhesions	Dilatation and aspiration	Supportive dilators, local estrogens in menopause	Relapse control
Asherman's syndrome	Hysteroscopic dissection of adhesions	Prevention of adhesions, repeated revision	There is no medicinal alternative
Post-ablation cornual retention	Targeted correction of obstruction	Refractory hysterectomy	High risk of recurrence with incomplete correction
Developmental anomalies	Temporary drainage as a bridge	Reconstructive surgery	Individual plan with visualization

Prevention

Primary prevention includes a gentle approach to intrauterine manipulation, prompt treatment of infections, and the use of image-guided techniques. After traumatic events, early monitoring and, if necessary, gentle rehabilitation of the cervical canal and uterine cavity are important. This reduces the risk of adhesions and stenosis. [45]

Secondary prevention aims to prevent recurrence after treatment: follow-up examinations, prevention of intrauterine adhesions when indicated, training in recognizing warning signs, and early referral if pain or amenorrhea recur. An individualized follow-up plan is especially important after endometrial ablation. [46]

Forecast

With timely evacuation and elimination of the cause of the obstruction, the prognosis is favorable: pain disappears, normal outflow is restored, and quality of life improves. Long-term results depend on the completeness of the correction and adherence to recommendations in the early postoperative period. [47]

The risk of recurrence is higher in cases of severe adhesions and post-ablation conditions. These groups require closer monitoring and readiness for repeated targeted correction. In cases of developmental anomalies, the outcome is determined by the quality of reconstruction and the timeliness of the intervention. [48]

FAQ

• Is this a life-threatening condition?

Danger arises when the contents become infected and severe pain occurs. Timely evacuation and, if necessary, antibacterial therapy make the prognosis favorable. [49]

• Is it possible to be cured without surgery?

If there is mechanical obstruction, drug therapy alone will not resolve the problem. Gentle instrumental drainage and correction of the underlying cause under visual control are typically required. [50]

• What to do if you have pain and no menstruation after endometrial ablation?

You should consult a doctor: cornual hematometra is possible. Targeted correction is often required, since simple dilation provides only a temporary effect. [51]

• Will hematometra affect future fertility?

With early treatment and elimination of the cause of obstruction, long-term reproductive outcomes are usually favorable. In Asherman syndrome, the prognosis depends on the severity of adhesions and the quality of hysteroscopic reconstruction. [52]