Hematometra describes distension of the uterine cavity with blood. It results from accumulation of menstrual blood or other hemorrhagic fluids in the uterine cavity due to obstruction of the cervix or lower uterine segment. Most common causes include cervical stenosis (postoperative, post-radiation, postmenopausal atrophy), cervical/endometrial carcinoma, congenital anomalies (imperforate hymen, vaginal septum), and cervical polyp/myoma. Clinically may present with pelvic pain, amenorrhea, or abnormal uterine bleeding. Imaging shows fluid distension of the uterine cavity; T1 hyperintense signal on MRI reflects blood products (methemoglobin) and enables acute/subacute/chronic staging. Identification of the underlying obstructive cause is critically important in diagnosis as malignancy (cervical or endometrial carcinoma) must be excluded.
Age Range
15-85
Peak Age
65
Gender
Female predominant
Prevalence
Uncommon
Hematometra results from complete or partial obstruction of the uterine cavity outlet (at cervical or vaginal level). Menstrual or postoperative blood flow is impeded and accumulates in the uterine cavity → progressive distension. Obstruction causes include cervical stenosis (radiation fibrosis, surgical scar, postmenopausal atrophy, post-conization), malignant obstruction (cervical or endometrial carcinoma), congenital anomalies (imperforate hymen, transverse vaginal septum, cervical agenesis), and benign lesions (cervical polyp, lower segment myoma). Accumulated blood undergoes hemoglobin degradation over time: acute stage oxyhemoglobin (T1/T2 isointense) → early subacute deoxyhemoglobin (T1 iso-hypointense, T2 hypointense) → late subacute methemoglobin (T1 hyperintense — intracellular: T2 hypointense, extracellular: T2 hyperintense) → chronic stage hemosiderin (T1/T2 hypointense). The paramagnetic properties of these hemoglobin degradation products create different signal characteristics on MRI, giving hematometra its time-dependent MRI appearance. On US, distension of the cavity with echogenic fluid is observed — blood products produce internal echoes unlike anechoic simple fluid.
The signature finding of hematometra is distension of the uterine cavity with fluid showing hyperintense signal on T1-weighted MR images. T1 hyperintensity is due to the paramagnetic effect of methemoglobin in subacute blood products. This finding is diagnostic in distinguishing from simple fluid collections (hydrometra — T1 hypointense) and pyometra (infected fluid — T1 variable).
On T1-weighted images, fluid collection with hyperintense signal within the uterine cavity is observed. This hyperintensity is due to methemoglobin in subacute blood products. Signal intensity varies with the stage of blood products — early subacute (intracellular methemoglobin) homogeneous hyperintense, late subacute (extracellular methemoglobin) more intense and homogeneous hyperintense. May be T1 isointense in acute stage (deoxyhemoglobin). In chronic cases, T1 signal decreases with hemosiderin deposition. If cavity wall (endometrium) is thin and smooth, benign etiology; thick, irregular, or enhancing wall raises malignancy suspicion.
Report Sentence
Distension with hyperintense signal on T1-weighted sequences observed in the uterine cavity; this finding is consistent with subacute blood products (methemoglobin) and compatible with hematometra.
T2 signal of hematometra on T2-weighted images depends on the stage of blood products. In late subacute stage (extracellular methemoglobin), T2 hyperintense signal is observed — the most commonly encountered pattern. In early subacute stage (intracellular methemoglobin), T2 hypointense signal is seen. In chronic cases, T2 hypointense peripheral rim may form due to hemosiderin deposition — this finding indicates chronic hematometra. Fluid-fluid level within the cavity reflects gravity-dependent accumulation of blood products at different stages.
Report Sentence
Distension with hyperintense signal on T2-weighted sequences in the uterine cavity accompanied by peripheral hypointense rim; these findings are consistent with subacute-chronic blood products and support the diagnosis of hematometra.
On B-mode ultrasonography, the uterine cavity appears distended with echogenic fluid. Unlike simple fluid (anechoic), internal echoes, debris levels, and heterogeneous echo pattern are observed in hematometra. Acute hemorrhage appears hyperechoic (bright), while organized blood clots show heterogeneous echogenicity. Fluid-debris level may form gravity-dependently. Endometrial thickness evaluation is important — thickened, irregular endometrium is suspicious for malignancy (endometrial carcinoma). The obstruction cause at the cervix should be investigated (polyp, myoma, stenosis, mass).
Report Sentence
Distension of the uterine cavity with echogenic fluid accompanied by internal echoes and debris levels consistent with blood products; hematometra is considered and the underlying obstructive cause should be investigated.
On non-contrast CT, high-density fluid accumulation in the uterine cavity is observed (40-70 HU). Fresh blood shows higher density than proteinaceous fluid (15-25 HU) and simple fluid (0-15 HU). Clotted blood may show even higher density values (70-90 HU). The uterine cavity may be expanded and myometrium thinned (prolonged distension). The underlying obstruction cause should be evaluated on CT — cervical mass, cervical stenosis, or vaginal obstruction is investigated. On contrast-enhanced CT, endometrial thickening and enhancement should be evaluated for malignancy.
Report Sentence
High-density (40-70 HU) fluid collection in the uterine cavity on non-contrast CT; these density values are consistent with blood products and hematometra is considered.
On DWI, hematometra shows variable signal. Proteinaceous and cellular blood products may demonstrate diffusion restriction (must be distinguished from T2 shine-through). High DWI signal and low ADC may be observed in clot areas. However, this finding must be differentiated from malignant intracavitary masses (endometrial carcinoma). In hematometra, diffusion restriction is expected within homogeneous fluid at the cavity center and not in the cavity wall; in endometrial carcinoma, solid wall thickening or intracavitary solid mass shows diffusion restriction.
Report Sentence
High signal on DWI observed in uterine cavity contents with partial signal decrease on ADC maps; these findings may be consistent with organized blood products but intracavitary solid lesion should be excluded.
On Doppler ultrasonography, the cavity contents of hematometra are avascular — no flow signal is observed on color or power Doppler. This finding is important for differentiation from intracavitary solid masses (endometrial polyp, carcinoma) because solid lesions demonstrate vascularity. Endometrial wall vascularity is preserved and may even be increased (inflammatory response). Increased vascularity in the cavity wall does not raise malignancy suspicion by itself but should be evaluated together with irregular wall thickening.
Report Sentence
No vascularity detected in the uterine cavity contents on Doppler examination; this finding is consistent with intracavitary fluid (hematometra) and does not support the presence of a solid mass.
Criteria
Fresh blood accumulation — symptom duration <72 hours. Oxyhemoglobin/deoxyhemoglobin predominant.
Distinct Features
T1 isointense or mildly hyperintense, T2 variable on MRI. Fresh blood density on CT (50-70 HU). Usually anechoic-hypoechoic fluid on US. Presentation with pelvic pain in emergency department.
Criteria
Accumulation between 3 days-4 weeks. Methemoglobin predominant — most characteristic appearance on MRI.
Distinct Features
Prominent T1 hyperintensity on MRI (methemoglobin). Early subacute: T2 hypointense (intracellular methemoglobin); late subacute: T2 hyperintense (extracellular methemoglobin). Most easily recognized stage.
Criteria
Accumulation longer than 4 weeks. Hemosiderin predominant — T2 hypointense rim. Frequently incidentally detected in postmenopausal women.
Distinct Features
T1 signal may be decreased on MRI (hemosiderin). T2 hypointense peripheral rim (hemosiderin deposition). Prominent blooming artifact on GRE/SWI sequences. Myometrium may be thinned (prolonged distension). Malignancy must be excluded (endometrial thickening?).
Distinguishing Feature
Endometrial carcinoma appears as intracavitary solid mass with enhancement and DWI restriction. Hematometra is a fluid collection without enhancement or solid component. Hematometra may be present in the background of endometrial carcinoma — cavity wall must be carefully evaluated.
Distinguishing Feature
Endometrial polyp appears as intracavitary solid vascular structure with feeding vessel on Doppler. Cavity contents of hematometra are avascular. Polyp can be clearly distinguished by SIS (saline infusion sonohysterography).
Distinguishing Feature
Cervical carcinoma may be the obstructive cause of hematometra. Appears as T2 hyperintense mass in the cervix with DWI restriction on MRI. Hematometra alone does not form a mass in the cervix — hematometra accompanying carcinoma should be considered when a cervical mass is present.
Urgency
urgentManagement
interventionalBiopsy
Not NeededFollow-up
3-monthUrgency of hematometra depends on the underlying cause. In benign-cause cases (cervical stenosis), cervical dilation and drainage is sufficient. In malignancy suspicion (hematometra in postmenopausal woman), endometrial biopsy and further evaluation is mandatory — endometrial carcinoma must be excluded. In congenital anomalies (imperforate hymen), surgical correction is required. In post-surgical or post-radiation cervical stenosis, dilation and stent may be applied. Follow-up US at 3 months monitors recurrence after treatment. Infected hematometra (pyometra) requires urgent drainage and antibiotic therapy.
Hematometra is a finding and the underlying cause should be investigated. Postmenopausal hematometra should be evaluated for endometrial carcinoma. Congenital anomaly (imperforate hymen) presents with cyclic pain in adolescent girls. Drainage and relief of stenosis are required in cervical stenosis.