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Research Article

Uterine arteriovenous malformation: A retrospective study from a tertiary center in southern Karnataka

[version 1; peer review: 1 approved, 1 approved with reservations]
PUBLISHED 03 Jun 2025
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Abstract

Introduction

Uterine arteriovenous malformation (AVM) is a rare cause of chronic to catastrophic vaginal bleeding. The basic pathology is an abnormal arteriovenous connection in the uterine myometrium, which is observed as an entangled serpentine vascular architecture on ultrasound. Color Doppler and higher imaging modalities with angiography are usually used to confirm a diagnosis.

Materials and methods

An electronic database of Obstetrics and Gynecology departments was searched for cases of arteriovenous malformation (AVM) between 2021 and 2025. Only cases of AVM confirmed by ultrasound or higher imaging were considered.

Results

We comprehensively reported 15 cases of arteriovenous malformations. All patients had acquired AVMs, with abnormal uterine bleeding as the main symptom in 93% of cases. The treatment provided was medical management in 26% of patients, conservative management by transcatheter embolization in 66%, and hysterectomy in 6.6%.

Conclusion

AVMs are rare in clinical practice, and an understanding of their pathophysiology and prompt diagnosis are highly important for managing this emergency. Fertility-preserving treatments include medical therapy and uterine artery embolization. Hysterectomy is the definitive treatment for this condition.

Keywords

Arterio-venous malformation, enhanced myometrial vascularity, uterine artery embolization, Progesterone

Introduction

Uterine arteriovenous malformation (AVM) is a rare, life-threatening condition. It is characterized by abnormal connections between the arteries and veins of the uterine myometrium. However, the exact prevalence of this condition remains unknown. These can be congenital or acquired. Acquired uterine AVMs are sometimes recognized as having enhanced myometrial vascularity (EVM). It refers to any uterine pathology resulting in increased myometrial vascularity regardless of residual tissue at conception.1,2 Uterine acquired AVMs are typically noticed in a multipara woman in her thirties.3 The common manifestations are menorrhagia, symptoms of anemia and catastrophic hemorrhage, which can lead to significant morbidity and, rarely, mortality. Ultrasound and CT angiography were the main diagnostic tests used. Treatment is generally multidisciplinary and involves obstetricians, radiologists, transfusion medicine professionals, and interventional radiologists. Medical, interventional (uterine artery embolization) and surgical methods are the different management modalities.

The objective of this study was to systematically study cases of acquired arteriovenous malformation and their impact on health. The article has followed strobe guidelines for the reporting of data.

Materials and methods

First, this was a retrospective study. Ethical committee clearance was also obtained in 23rd April 2025. (IEC1-166/2025). The search was performed from January 2021 to February 2025 for all patients admitted with an AVM diagnosis. Details of the AVM cases were obtained from the electronic database system or from the medical records section of the Kasturba Medical College, Manipal, Karnataka. Patient enrollment was performed only after confirmation of the diagnosis by uterine power Doppler or after imaging with angiography. Informed written consent was obtained. Data concerning the patient’s age, presenting symptoms, obstetric history, comorbid conditions, detection modality, and treatment provided were obtained. Patients with inconclusive diagnoses were excluded from the study.

Results

During the abovementioned time frame, a total of 19 cases of AV malformation were found, and 15 cases had appropriate doppler or higher imaging diagnosis. Patient characteristics are summarized in Table 1. The age range of the patients was 24–40 years. The presenting symptom was bleeding or spotting per vagina in 93.3% of patients. A total of 86.8% of patients were referred, and a referral was observed 4 days to 10 weeks after the trigger event. A total of 13.2% of patients had severe multiple system involvement. The distribution of gravidae was as follows: primary (33.3%), second (26.6%), third (19.9%), fourth (13.2%), and fifth (6.6%) gravidae. A total of 46.2% had previous cesarean sections and 19% had undergone vaginal delivery. A total of 19.98% of women had a history of previous pregnancy mishaps in the form of first-trimester abortions. A total of 93.34% of women had early pregnancy loss or MTP as an inciting event between 5 and 14 weeks. A total of 79.9% of patients required dilatation and curettage (D&C) or MVA before or after AVM diagnosis. One patient presented with normal delivery. The reported hemoglobin level was between 4.2 and 11 during treatment, and 46.2% of the patients received blood ± blood product transfusions. hCG observed at the time of admission varied between 0.1 and 109 mIU/ml, which became negative during follow-up visits. Two patients delivered after treatment (Uterine Artery Embolization), one of whom had stage 1 gestational trophoblastic neoplasia.

Table 1. Demographic information of AV malformation cases.

Age Presenting symptom Referral or booked Diagnosis after primary event Gravidae para Previous abortion Previous delivery route Inciting event Surgical event 1=D&C
2=MVA
Hb changes (gram%) PRBC transfusion in pints B hCG at presentation (mIU/ml)
40Bleeding, abdominal painR3 weeks421 SA2 CDSA: 11 weeks1*6.2117
28Altered sensorium x 1 day, FeverR6 weeks10------------SA: 8 weeks1*4.929.4
30Prolonged bleedingR2 weeks21--------1 CDMTP*: 15 weeks1*5.73109
24AsymptomaticR3 weeks10--------------MTP*: 10.4 weeksNo11.7None39
35Secondary PPHR6 weeks22--------2 CDPostpartum 44 daysNo450.1
28Sudden loss of consciousness and breathlessR5 weeks421 MTP2CDMTP for MA at 7 weeks1* and 1 (3 months later)11None0.2
38Giddiness, bleeding palpitationR1 weeks21------VDMTP for BO at 7 weeks1* (1.5 months later)4.93 PRBCa1.5
30Bleeding P/vR2 weeks522 MTPs2 CDMTP* at 10 weeks1*, 2 (later)12None10.3
31abdominal pain, bleeding PVR4 days322 CDMTP* at 6 weeks2 later8None34
25Persistent bleeding PVB4 weeks10----------MA at 8 weeks2*10None20
27On and off bleeding P/VR10 weeks32-----2 VDMA at 10 weeks1*4.637.23
35Continuous bleeding PVR4 weeks21-------VDMA at 10 weeks1*10.2None0.6
31MenorrhagiaR8 weeks10--------------SA at 4 MA16.451.3
33SpottingB25 days32-----2 CDMA at 14 weeks28None0.1
27Bleeding PVB4 weeks10-----------MA at 13 weeks29.6None61

The diagnostic modalities and treatments are summarized in Table 2. All patients underwent transvaginal ultrasound, and confirmation was provided by CT angiography in 59.4%, MRI angiography in 19.9%, digital subtraction angiography (DSA) in 13.3%, and contrast-enhanced computed tomography (CECT) in 6.6%. We observed that posterior uterine wall lesions were more common than anterior uterine wall lesions. The final treatment options included uterine artery embolization/transcatheter embolization (TCE) (66%), surgical hysterectomy (6.6%), and conservative management (26.6%). Failure of conservative management was observed in 2 patients (one after treatment with OC pills and one after treatment with progesterone). Injectable leuprolide (2 patients) and progesterone (2 patients) treatment resulted in satisfactory control of bleeding. One patient with medical management required an additional balloon tamponade for symptom control. Four procedures involved the use of PVA exclusively as embolization material (500–710 μm), one involved the use of glue, and five procedures involved the combination of both as embolization materials. The glue used was NCBA with a concentration between 20 and 40% and 2–3 cc used for a single artery, and is often used with a lipiodol emulsion. All the patients underwent bilateral uterine artery embolization (UAE). Figure 1 shows an ultrasound depiction of the AVM. MRI and Angiography findings of the AVM are depicted in Figures 2 and 3, respectively. Figure 4 illustrates the UAE procedure.

Table 2. Diagnosis and management of the cases with AVMs.

CasesLocation of lesionMRI/CT/DSAProcedureDefinitive treatmentICU admissionHospital stay Follow upOther remarks
1Anterior -Left lateral uterine wallMRI** Multiple serpentine flow voids with early draining veins 2x2 cmNidus occlusion by 33% NBCA glue, 2 ccB/L UAEHDU7 days3 monthsFertility not desired
2Anterior uterine wall*Dilated vessels within myometrium of 2.5x2.5 cm3 cc NBCA glue, right UA: PVA particle 350-500 micronsProgesterone & DMPA failure
B/L UAE
ICU17 days4 monthsFertility desired
Infection
3Antero-lateral uterine wall*7x5x4.7 cm predominantly cystic area, aneurysmal dilation40% NCBA glue, 2cc. additional PVA particlesB/L UAEHDU5 days5 monthsFertility not desired
4Fundal and Right lateral wallMRI**3.4x2.5x2.2 cm, arterial enhancement with early drainageconservativeLeuprolide for 3 monthsNa5 days6 monthsFertility desired
5Fundal and anterior wallDSA 3x2.5 cm hypervascular area with turbulent flow in fundal and anterior wallPVA 500-710 micronsPrimolute failure
B/L UAE
HDU10 days36 monthsFertility not desired
MTP for subsequent pregnancy
6Right entire posterolateral wallCECT: nidus of vessels involving full thickness of myometrium, 5x4.5 cmconservativeNorethisterone
Tapering doses
Na6 days29 monthsSterilization done infection and PID
7Posterior wall of myometrium*2x2.3 cm nidusDeferred UAETAH, BS, Na6 days28 monthsfertility not desired detected with chocolate cyst
8Posterior endometrial/8*hypervascular area at endomyometial wallPVA particles and gel foamsB/L UAENa5 days29 monthsFertility not desired afterwards MVA for irregular bleeding
9Left fundal posterior wall*2x2.3 cm nidus at posterior wallPVA particlesB/L UAEHDU4 days36 monthsFertility not desired
10Posterior fundal myometrium*left lateral wall and draining to LUAB/L UAE with NBCA glue, 20% glue:lipiodolB/L UAENa5 days12 monthsDelivered, had GDM
11Fundal myometrium*multiple tortuous vascular channels20% glue-lipodol emulsionB/L UAEICU3 days24 monthsFertility not desired
Had hematometra evacuation after a month
12Outer fundal left myometriumMRI**: nidus at fundus 2x2.1 cm, vascular malformation in B/L adnexa and outer uterine wall 33%, 3 cc NBCA glue and lipidol emulsionB/L UAE
OC pills failure
no3 days12 monthsOne live child and fertility desired
13Posterior uterine wallCECT, DSA Nidus of 3x2.5 cmPVA particlesB/L UAEno7 days42 monthsDelivered twice, had HDP and one GTT stage 1
14Right posterior lower body myometrium*right posterior wall nidus of 2x2 cmconservativeProgesterone, cervical tamponadeno6 days3monthsFertility not desired past history of recent infection
15Left posterior myometrial wall*hyper vascular lesion 3x2.2 cm, Conservative/Leuprolide and aromatase inhibitorsNo10 days3 monthsFertility desired
Past history of infection

* CT angiogram; PVA, polyvinyl alcohol; NCBA, N-butyl cyanoacrylate.

0635e9b7-6438-48c3-a261-213b626fd2ec_figure1.gif

Figure 1. a, b: Ultrasound diagnosis of AVM suggests convoluted vascular structure (red color) in the myometrium with color signals.

0635e9b7-6438-48c3-a261-213b626fd2ec_figure2.gif

Figure 2. a, b, c: MRI depicting highly vascular structure (Blue arrow) suggestive of AVM in uterine myometrium.

0635e9b7-6438-48c3-a261-213b626fd2ec_figure3.gif

Figure 3. a, b, c: Angiography suggestive of uterine AVM.

0635e9b7-6438-48c3-a261-213b626fd2ec_figure4.gif

Figure 4. Uterine artery embolization procedure depicting pre-procedure, selection process and post-procedure arterial tree.

The hospital stay was 3–17 days, and nearly 19% of the patients had repeated admissions due to hematometra (n=1) and bleeding per vagina (n=2). ICU admissions were observed in two patients: one for temporal mesial sclerosis and another for multisystem dysfunction. 26% the infected patients had infections in the last 3 months, including hepatitis (n=1), endometritis (n=2), endocarditis, and pancreatitis (n=1).

Discussion

AVMs are rare entities, and two varieties of uterine AVMs have been identified. Congenital AVMs are present from birth and develop during erroneous angiogenesis at the fetal stage, leading to aberrant formation of the primitive capillary plexus with the absence of muscular and collagen tissue.4,5 Congenital or true AVMs are diagnosed either as isolated uterine entities or as a part of extensive pelvic AVMs. Only a few hundred cases have been reported because of the rarity of the condition, and the first case was reported in 1926.4,6 The incidence of AVMs is 0.63 following abortion or parturition.7 The acquired AVMs can be secondary to surgical procedures or pathologies. The most common reason is dilation and curettage (D&C) after abortion or MTP (medical termination of pregnancy).8 Uterine surgeries, such as myomectomy or cesarean delivery, can be iatrogenic. It can occur even after a normal delivery. Certain neoplastic conditions, such as gestational trophoblastic neoplasia and endometrial or cervical carcinoma, can even result in AVM.8 It has been reported following infection, hysteroscopy, intrauterine device placement, and cesarean site pregnancy in offspring exposed to diethylstilbosterone.1 The number of acquired AVMs has increased due to both improved diagnosis and increased number of uterine surgeries in recent years.9 In 2015, the international society of ultrasound in obstetrics and gynecology coined the term enhanced myometrial vascularity (EMV) for RPOC-related AVMs.2,10,11 It was almost exclusively meant in the context of recent pregnancy and hence in women of reproductive age.12 In the literature, traumatic AVMs, arteriovenous shunts, EVMs and arteriovenous fistulas are the terms used interchangeably and are difficult to differentiate.

RPOC-related AVMs are formed between necrotic chorionic villi and venous sinuses of scar tissue. Histologically, a uterine AVM is an arteriovenous fistula between the intramural arterial branches of the uterine arteries and the myometrial venous plexus, bypassing the normal capillary system, which has an interrupted or absent elastic membrane and completely absent muscular tunica media.13

The spectrum of presenting symptoms varies from asymptomatic detection to catastrophic hemorrhage.14 True AVMs can have additional varicosities in the pelvic or perineal area.15 The usual symptoms are abnormal vaginal bleeding leading to anemia and, sometimes, life-threatening hemorrhagic shock. Other symptoms include pelvic pain, urinary frequency and dyspareunia.16 If not diagnosed and treated in a timely and proper manner, secondary cardiorespiratory or cerebrovascular complications may occur, which can rarely progress to multiple organ failure. The primary complaint was bleeding in 93% (14/15) of patients. Atypical symptoms such as fainting episodes, giddiness, breathlessness, and altered sensorium were present in three patients. One patient had acute kidney injury and another patient had mesial temporal sclerosis. The relationship between AVM and neuronal symptoms, such as temporal sclerosis, is not well established. However, we suggest utmost vigilance during medical therapy for patients with vaginal bleeding to prevent multisystem damage. A referral delay was observed, which needed to be curtailed by appropriate measures to achieve better outcomes.

A transvaginal scan is a primary, cost-effective, and simple screening modality, and AVMs are suspected on grayscale as enlarged anechoic vessels in the myometrium/parametrium or as myoendometrial masses with myometrial thickening.6,17 Doppler interrogation is often diagnostic, and AVMs are depicted as enlarged, entangled, hypervascular masses with high turbulence and aliasing. It exhibits a multidirectional flow. On power Doppler, it has a high velocity and low resistance flow. It has a high peak velocity and a low RI. It has prognostic ability, as it can stratify patients at high or low risk.4 Thus, ultrasound and color Doppler are valuable tools for identifying AVMs.18 3D color Doppler provides better delineation of feeding and draining vessels. We performed grayscale and color Doppler in all patients; however, power Doppler values were not consistently followed in our study.

MRI or CT is indicated when USG is unsatisfactory.6 It helps with pre-procedure planning. MRI/CT angiography is a better diagnostic modality for determining the lesion outlines. Uterine artery angiography (UAA), a specific application of digital subtraction angiography, is the gold standard test.4,6 AVMs are characterized by tangled vessels containing nests, feeding arteries, draining veins, and brisk venous depletion. The utility of UAA is generally restricted for patients who would benefit from UAE because of the invasive nature of the test.17 UAA helps in differentiating AVMs from pseudoaneurysms and other vascular lesions. Overdiagnosis can occur if the disease is diagnosed using ultrasonography alone. Angiography is not always needed for diagnosis, but is essential before planning operative management or arterial embolization. Hysteroscopy may be used to diagnose and manage AVMs.13 We used DSA or CT/MRI angiograms as diagnostic or pretreatment tests in 93.4% of the patients.

Treatment

The treatment is based on the severity of symptoms and ranges from conservative to uterine artery embolization.8,19 Owing to the rarity of this condition, there is a paucity of high-level evidence guiding clinicians with respect to its management.19 Spontaneous resolution has been mentioned in asymptomatic women, with a wait-and-watch policy for postpartum/postabortion cases.20 The medications used in the literature vary across the studies and for variable times. Progestins and gonadotropin-releasing hormone analogs are the most frequently used medications. Chemotherapeutic agents such as methotraxate, combined oral contraceptive pills, uterotonic (methyl ergonovine), danazol, ulliprtistol, and aromatase inhibitors, either in combination or alone, are less frequently prescribed.19 The success rate varies between 42% and 100% across the studies. Medical management is prescribed either as primary treatment or after failure of transcatheter embolization (TCE).8,19 A systematic review by Rosen evaluated 32 studies, irrespective of study design; 121 patients were managed with medical treatment, with a success rate of 88%. Progestins, GnRH analogs, and methotrexate are more efficacious than other medical agents are.19 Medical management has the advantage of universal accessibility and is less expensive. It also has a higher fertility-sparing capacity. However, for patients with significant bleeding, medical management failure, and hemodynamic instability, UAE/TCE, internal iliac ligation, or other surgical procedures such as hysterectomy are alternative treatments. We reported 33% failures with medical management in patients who were managed with TCE. The success rate of UAE/TCE is reported to be 71–91%.8,21

No TCE failure was observed. Importantly, repeat embolization, medical management, or surgery are secondary options for patients with UAE failure.8 Mild pelvic pain was observed in 20% of the patients in the present study after TCE, which was controlled by analgesics. Postprocedural fever is another complication of post-embolization syndrome. Iatrogenic vessel dissection, contrast-induced nephrotoxicity, and puncture site hematoma are procedure-related complications.8 The decision for unilateral or bilateral TCE was made by an interventional radiologist in our case.

Hysterectomy is indicated only if future fertility is not desired and if immediate medical facilities are not available. It should be performed by experienced pelvic surgeons.22 It is the final treatment if conservative medical treatment or UAE fails, leading to life-threatening hemorrhage. Minimally invasive surgical techniques through the laparoscopic uterine artery or internal iliac occlusion through nonabsorbable clips have also been mentioned in the literature, either following failure of UAE or as primary procedures.23 Bipolar coagulation of the uterine arteries is a modality of treatment.24 The resection of myometrial lesions by laparoscopy or hysteroscopy has been advocated in the literature.13,25

Successful pregnancy and delivery have been described in the literature,26 and we achieved a total of three successful pregnancies after TCE in two patients. The complications observed were mild preeclampsia (one patient) and gestational diabetes (one patient); however, all three neonates were normal. One pregnancy was diagnosed as gestational trophoblastic tumor stage I. There are few studies on fertility outcomes after TCE, but a higher risk of placental abnormalities has been described in the literature.

The main limitations of this study are its retrospective nature and the small sample size. The diagnostic method varies across patients; hence, it cannot provide exclusive power Doppler data for diagnosis. Few patients were lost to follow-up; hence, data on the recurrence of symptoms requiring alternate/definitive therapy are not available. However, considering the rarity of this condition, we presented the exclusive details of patients with AVMs, which is the main strength of this study.

Conclusion

AVMs are rare; however, their incidence is increasing owing to the increase in the number of uterine surgeries and improvements in diagnosis. The primary investigating modality is ultrasound with color and power Doppler imaging. Uterine artery angiography is a diagnostic method used for the detection of AVMs. Owing to these rare conditions, no treatment guidelines are available. Each case must be individualized. Conservative treatment is an option in mild cases. It also helps retain fertility. Surgical management is the treatment of choice in severe cases without reproductive desire.

Ethical approval

The study was approved by Kasturba Medical College and Kasturba Hospital, Institutional Ethical Committee, IEC 1: 166/2025. Date: 23 April 2025.

Ethical standards and research involving human participants: The study involving human participants followed the ethical standards of the institute’s ethical and research committee and the 1964 Helsinki Declaration and its later amendments.

Consent

Written informed consent was obtained from patients.

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Hebbar S, Kramadhari H, Sharma R et al. Uterine arteriovenous malformation: A retrospective study from a tertiary center in southern Karnataka [version 1; peer review: 1 approved, 1 approved with reservations]. F1000Research 2025, 14:554 (https://doi.org/10.12688/f1000research.164989.1)
NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
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ApprovedThe paper is scientifically sound in its current form and only minor, if any, improvements are suggested
Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit.
Not approvedFundamental flaws in the paper seriously undermine the findings and conclusions
Version 1
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PUBLISHED 03 Jun 2025
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Reviewer Report 23 Aug 2025
Antonella Vimercati, University of Bari “Aldo Moro", Bari, Italy 
Approved with Reservations
VIEWS 10
Differentiation between AVM and enhanced myometrial vascularity (EMV) and retained products of conception is relevant in clinical practice, and it currently represents a challenge. An increasing number of studies describe the enhanced myometrial vascularity associated with retained products of ... Continue reading
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CITE
HOW TO CITE THIS REPORT
Vimercati A. Reviewer Report For: Uterine arteriovenous malformation: A retrospective study from a tertiary center in southern Karnataka [version 1; peer review: 1 approved, 1 approved with reservations]. F1000Research 2025, 14:554 (https://doi.org/10.5256/f1000research.181583.r396028)
NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article.
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Reviewer Report 28 Jul 2025
Paolo Ivo Cavoretto, IRCCS San Raffaele Scientific Institute, Milan, Italy 
Approved
VIEWS 10
This is a nice study with interesting results.

The pictorial essay by Cavoretto and Cioffi on gestational trophoblastic neoplasia illustrates key imaging features of the disease. Notably, it highlights the early precursors of arteriovenous malformations associated with ... Continue reading
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HOW TO CITE THIS REPORT
Cavoretto PI. Reviewer Report For: Uterine arteriovenous malformation: A retrospective study from a tertiary center in southern Karnataka [version 1; peer review: 1 approved, 1 approved with reservations]. F1000Research 2025, 14:554 (https://doi.org/10.5256/f1000research.181583.r394304)
NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article.

Comments on this article Comments (0)

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Alongside their report, reviewers assign a status to the article:
Approved - the paper is scientifically sound in its current form and only minor, if any, improvements are suggested
Approved with reservations - A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit.
Not approved - fundamental flaws in the paper seriously undermine the findings and conclusions
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