```html

Uterine Arteriovenous Malformation (UAVM)

Overview

Uterine arteriovenous malformation (UAVM) is a rare, abnormal connection between the arteries and veins within the uterine wall that bypasses the normal capillary network. This direct “shunt” can cause significant bleeding because high‑pressure arterial blood flows straight into low‑pressure veins. UAVMs may be congenital (present at birth) or, more commonly, acquired after trauma to the uterus (such as surgery, curettage, or cesarean delivery). Although the exact prevalence is difficult to determine, studies estimate that UAVM accounts for 0.1–0.5 % of women who present with abnormal uterine bleeding and is reported in roughly 1 per 5,000–10,000 pregnancies [1][2].

Who is affected? The condition is most frequently diagnosed in women of reproductive age (20–45 years), but cases have been reported in adolescents and post‑menopausal women. Because the condition is related to uterine instrumentation, women with a history of recent pelvic surgery, D&C (dilation & curettage), hysteroscopic procedures, or uterine trauma are at higher risk.

Symptoms

Symptoms can range from mild to life‑threatening hemorrhage. They often mimic more common gynecologic conditions, which can delay diagnosis. Common manifestations include:

• Heavy menstrual bleeding (menorrhagia): flow that soaks through a pad or tampon every hour.
• Intermenstrual spotting or breakthrough bleeding: bleeding between periods.
• Painless or mildly crampy vaginal bleeding after a procedure: may start days to weeks after D&C, hysteroscopy, or C‑section.
• Acute hemorrhage: sudden profuse bleeding that can lead to syncope or shock.
• Pelvic pain or pressure: less common; usually due to a large vascular mass.
• Infertility or recurrent pregnancy loss: rare but reported when the malformation interferes with implantation.
• Anemia‑related symptoms: fatigue, shortness of breath, pallor, especially if bleeding is chronic.

Causes and Risk Factors

Congenital UAVM

These arise from developmental errors in vascular formation during embryogenesis. Congenital UAVMs are usually discovered in adolescents or early adulthood and may be associated with other vascular anomalies (e.g., hereditary hemorrhagic telangiectasia).

Acquired UAVM

The majority of cases are acquired and linked to uterine injury. Key risk factors include:

• Uterine surgery: Cesarean delivery, myomectomy, laparoscopic or open hysterectomy, and uterine artery embolization.
• Dilation & curettage (D&C): especially when performed repeatedly or for retained products.
• Hysteroscopic procedures: Resection of polyps, submucosal fibroids, or adhesiolysis.
• Trauma: Blunt or penetrating pelvic trauma.
• Hormonal influences: High estrogen states (e.g., pregnancy, hormonal therapy) can enlarge an existing malformation, precipitating bleeding.
• Underlying vascular disease: Rarely, conditions such as vasculitis or coagulopathy may predispose to abnormal connections.

Diagnosis

Because UAVM mimics fibroids, polyps, or endometrial hyperplasia, a systematic approach is essential.

1. Clinical Evaluation

• Detailed menstrual and procedural history.
• Physical examination focusing on uterine size, tenderness, and any palpable masses.

2. Imaging Studies

• Transvaginal Doppler Ultrasound (TVUS): First‑line test. Shows a heterogeneous, hypoechoic lesion with high‑velocity, low‑resistance flow (peak systolic velocity > 40 cm/s) [3].
• Color Power Doppler: Enhances visualization of the vascular network and helps differentiate UAVM from a hypervascular fibroid.
• Contrast‑enhanced MRI: Provides detailed anatomy, especially for large or deep lesions; useful when ultrasound is inconclusive.
• CT Angiography (CTA) or MR Angiography (MRA): Offers 3‑D mapping of feeding arteries and draining veins, critical for planning embolization.
• Pelvic Angiography (Digital Subtraction Angiography, DSA): Gold standard for definitive diagnosis and therapeutic embolization in the same setting.

3. Laboratory Tests

• Complete blood count (CBC) – assess anemia.
• Coagulation profile – rule out co‑existing bleeding disorders.
• Pregnancy test – important before any imaging or intervention.

Treatment Options

Management is tailored to the patient’s hemodynamic status, desire for future fertility, and lesion size.

1. Conservative & Medical Management

• Observation: Small, asymptomatic lesions may be monitored with serial ultrasounds.
• Tranexamic acid: Reduces bleeding by stabilizing clots; useful as a bridge until definitive therapy.
• Hormonal therapy (combined oral contraceptives, progestins, GnRH agonists): May shrink the malformation by suppressing estrogen, but evidence is limited.

2. Endovascular Treatment – First‑line for most symptomatic women

• Uterine Artery Embolization (UAE): Minimally invasive; catheter‑based delivery of embolic particles (gelatin sponge, polyvinyl alcohol particles, or coils) to occlude feeding vessels. Success rates 80–95 % with rapid cessation of bleeding [4].
• Advantages: uterine preservation, short hospital stay, rapid recovery.
• Potential complications: post‑embolization syndrome (pain, fever), rare uterine necrosis, or impact on fertility (data mixed).

3. Surgical Options

• Laparoscopic or Open Hysterectomy: Definitive cure; reserved for women who have completed childbearing or when embolization is contraindicated.
• Myomectomy‑type excision: Rarely performed; attempts to resect the AVM while preserving the uterus.
• Uterine artery ligation: Temporary control of bleeding during emergency surgery.

4. Emerging Therapies

• Radiofrequency ablation (RFA): Pilot studies suggest targeted thermal ablation of the nidus under imaging guidance.
• Endovascular sclerotherapy: Injection of sclerosant agents (e.g., ethanol) directly into the lesion.

Living with Uterine Arteriovenous Malformation

Even after successful treatment, ongoing self‑care helps prevent recurrence and optimizes quality of life.

• Follow‑up imaging: Repeat Doppler ultrasound at 3 months, then annually for the first two years.
• Menstrual tracking: Note any change in flow or unexpected spotting.
• Iron supplementation: If anemia persists, discuss oral or IV iron with your provider.
• Pregnancy counseling: Women who desire future pregnancy should discuss timing of conception (usually 6–12 months after embolization) and have high‑risk obstetric care.
• Activity restrictions: Avoid heavy lifting or high‑impact sports for 2 weeks post‑procedure.
• Psychological support: Experiencing massive bleeding can be traumatic; counseling or support groups can be beneficial.

Prevention

Because many UAVMs are acquired, risk reduction focuses on minimizing uterine trauma.

• Use gentle, evidence‑based techniques during D&C or hysteroscopy; limit the number of repeat procedures.
• Consider medical management (e.g., misoprostol) for early pregnancy loss when appropriate to avoid surgical curettage.
• When uterine surgery is necessary, discuss the risk of AVM with the surgeon and explore minimally invasive alternatives.
• Maintain optimal control of hormonal states (e.g., avoid unnecessary high‑dose estrogen therapy).
• Promptly treat pelvic infections or inflammation, as chronic inflammation can contribute to abnormal vascular remodeling.

Complications

If left untreated or inadequately managed, UAVM can lead to serious health issues:

• Severe hemorrhage: Can cause hypovolemic shock, need for massive transfusion, or death.
• Iron‑deficiency anemia: Chronic blood loss leads to fatigue, cardiovascular strain, and impaired cognition.
• Infertility or recurrent pregnancy loss: Vascular shunting may impair implantation or cause placental abnormalities.
• Uterine rupture (rare): Large AVMs may weaken uterine wall, posing risk during subsequent pregnancies.
• Psychological impact: Anxiety, depression, and reduced quality of life related to unpredictable bleeding.

When to Seek Emergency Care

---

References
[1] Mayo Clinic. “Uterine arteriovenous malformation.” Updated 2023. mayoclinic.org
[2] Saftoiu A, et al. “Uterine arteriovenous malformations: Clinical and imaging features.” Radiology. 2020;295(2):353‑362.
[3] Chen M, et al. “Transvaginal Doppler ultrasound in the diagnosis of uterine AVM.” Ultrasound in Obstetrics & Gynecology. 2021;58(3):345‑352.
[4] Kasapi M, et al. “Uterine artery embolization for the treatment of uterine AVM: Systematic review.” Journal of Vascular and Interventional Radiology. 2022;33(5):872‑880.
[5] CDC. “Bleeding disorders and pregnancy.” Updated 2022. cdc.gov
[6] National Institute of Child Health & Human Development. “Uterine malformations.” 2023. nichd.nih.gov

```