Uterine fibroids (leiomyomas): Treatment with uterine artery embolization

INTRODUCTION — Uterine artery embolization (UAE) was introduced for the treatment of symptomatic uterine fibroids (leiomyomas) in 1995 [1,2]. UAE treatment of fibroids is performed worldwide. Fibroids are a common gynecologic problem and result in symptoms that impact quality of life and may result in anemia or other adverse effects. There are many options for treatment, including hormonal therapy, hysteroscopic or abdominal myomectomy, and hysterectomy. UAE provides a minimally invasive and uterine-sparing treatment option.

This topic reviews UAE for uterine fibroids. The diagnosis and general principles of management of fibroids are discussed in detail separately. (See "Uterine fibroids (leiomyomas): Epidemiology, clinical features, diagnosis, and natural history" and "Uterine fibroids (leiomyomas): Treatment overview".)

RELEVANT ANATOMY — The majority of the blood supply to the uterus derives from the uterine arteries, and there is also collateral perfusion from the ovarian arteries (figure 1). The uterine arteries originate from the anterior division of the internal iliac arteries in the retroperitoneum (figure 2). They may share a common origin with the obliterated umbilical artery, internal pudendal, or vaginal artery. The ovarian arteries arise from the abdominal aorta. The right ovarian vein returns to the inferior vena cava while the left ovarian vein returns to the left renal vein. (See "Surgical female pelvic anatomy: Uterus and related structures", section on 'Vasculature'.)

PATIENT SELECTION

Indications — UAE is a treatment option for patients with symptomatic uterine leiomyomas. There are many treatment options for uterine fibroids and the clinician must guide the patient through this choice. (See "Uterine fibroids (leiomyomas): Treatment overview".)

Ideal candidates for UAE include patients with all of the following characteristics [3-5]:

●Heavy menstrual bleeding or dysmenorrhea caused by intramural fibroids

●Premenopausal

●No desire for future pregnancy

For patients with these characteristics, a high symptom control rate, satisfaction, and quality of life can be achieved for up to 10 years after treatment [5-8]. (See 'Efficacy' below.)

If bulk-related symptoms (eg, sensation of pressure in the lower abdomen, nocturia, urinary frequency, and urinary incontinence) are the only symptoms, the efficacy of UAE is questionable [9,10]. The embolization versus hysterectomy randomized trial (EMMY) showed no significant improvement compared with baseline in bulk-related complaints [3]. Some prospective cohort studies have found, however, a significant improvement in bulk-related symptoms even in the long-term [11,12]. It is also not usually used to treat infertility related to fibroids, since a desire for future childbearing is a relative contraindication. (See 'Efficacy' below.)

UAE is also a potential option for treatment of uterine adenomyosis, but the data are limited regarding efficacy for this indication [13]. A literature review included 1049 patients with adenomyosis treated with UAE and reported significant improvement in symptoms in 83.1 percent of patients [13]. Uteri with adenomyosis combined with fibroids tend to have better results than uteri with only adenomyosis. However, these were low-quality data from series with no control group. Management of uterine adenomyosis is discussed in detail separately. (See "Uterine adenomyosis".)

Prognostic factors — There are limited data regarding prognostic factors to predict the effect of UAE on fibroid volume, symptoms, and need for reintervention. The largest studies did not show strong predictors, and some smaller studies have reported predictors, but these may be underpowered. Prognostic factors that have been described include:

●Preprocedure:

•Predictors of a greater improvement in symptom score following the procedure include a presenting symptom of heavy menstrual bleeding (rather than other symptoms), smaller leiomyoma size, and submucosal location [14].

•Hypervascular fibroids, detected with contrast-enhanced imaging, before UAE predict a high regrowth-free interval [15]. Another study found the opposite: poorly vascularized fibroids had a lower chance of recurrence than highly vascularized fibroids, even though initial volume reduction was less in hypovascular fibroids [16]. In our practice, we use magnetic resonance imaging, but Doppler ultrasound or contrast-enhanced ultrasound may also be used.

•Larger fibroids and more numerous fibroids predict higher symptom recurrence [17].

●During the procedure:

•Unilateral UAE predicts failure (failure defined as subsequent hysterectomy) [18].

Contraindications — UAE is absolutely contraindicated in patients who currently have the following conditions:

●Asymptomatic fibroids

●Pregnancy

●Pelvic inflammatory disease

●Uterine malignancy

Several relative contraindications have been proposed:

●Desire for future pregnancy – Myomectomy has been the standard approach for patients with symptomatic fibroids who wish to conceive. When UAE was introduced as a treatment for fibroids, a desire for future pregnancy was considered an absolute contraindication because there was concern that poor uterine perfusion following UAE would negatively impact fertility and result in obstetric complications or adverse fetal effects. There are some reassuring data from patients who have undergone UAE and then become pregnant. High-quality comparative studies are limited and mostly underpowered. (See 'Reproductive outcomes' below.)

We suggest not performing UAE in patients who desire future pregnancy. However, UAE may be reasonable in patients with severe anemia or symptoms associated with fibroids, those who have failed conservative measure and have contraindications to surgery, or those who consent to UAE within an approved research protocol. Patients should receive counseling about the potential risks of UAE to a future pregnancy.

The American College of Obstetricians and Gynecologists states that the effect of UAE on pregnancy remains understudied but makes no recommendation of whether desire for a future pregnancy is a contraindication [19-21]. (See 'Reproductive outcomes' below.)

●Postmenopausal status – The procedure is indicated primarily for premenopausal patients since fibroids tend to decrease in size and symptoms improve or resolve after menopause. An enlarging uterus after menopause should raise the suspicion of a malignancy and careful follow-up is warranted.

●Fibroid characteristics:

•Location – Previously, subserosal pedunculated fibroids with a narrow stalk (stalk <50 percent in diameter in comparison with the largest diameter fibroid) were considered a relative contraindication because these fibroids may detach intraperitoneally and be associated with sterile peritonitis [22]. However, these is no strong evidence that such fibroids cannot be treated with UAE, though it may be preferred to avoid UAE when only a pedunculated subserosal fibroid is present. In a meta-analysis of 11 observational studies including patients with pedunculated subserosal fibroids undergoing UAE, the risk of complication was low (1.7 percent) and the majority of such complications were classified as mild [23]. Moderate (eg, torsion of the fibroid or persistent bleeding requiring surgery) and severe complications (eg, fibroid necrosis resulting in bowel obstruction) occurred in three patients. Volume reduction and satisfaction rates are similar to those that were non-pedunculated.

Similarly, submucosal fibroids treated with UAE may detach and be expelled vaginally through either bulk expulsion (losing the entire fibroid vaginally) or through sloughing (vaginal discharge until the fibroid has dissolved). Incidence is typically reported as 5 to 15 percent [22]. Even though not an absolute contraindication, patients with fibroids that protrude into the uterine cavity should be carefully counseled regarding the possibility of expulsion.

•Size or number of fibroids – The volume of necrosis after UAE in a large fibroid uterus can be substantial with a proportionate level of postprocedural pain and risk of infection. However, no clear threshold for the size of the uterus or size or number of fibroids has been established as a contraindication. The only study to address this question was a case series of patients with a dominant fibroid of >10 cm and/or a uterine volume of >700 cm that found no increase in the risk of serious complications [24].

●Contraindications to radiologic contrast agents.

PREPROCEDURE EVALUATION

History and physical examination — The patient should be asked regarding fibroid-related symptoms (eg, heavy or prolonged menstrual bleeding, pelvic pain, bulk-related symptoms). A medical history should be taken, including an obstetrics and gynecology history and medical and surgical history relevant to the procedure. Patients should be asked about the impact of symptoms on quality of life and what their goals and expectations for the procedure are. They should be asked whether they are planning a future pregnancy.

A pelvic examination is performed to assess the size and mobility of the uterus. The examination for a fibroid uterus is discussed in detail separately.

The evaluation of patients with fibroids is discussed in detail separately. (See "Uterine fibroids (leiomyomas): Epidemiology, clinical features, diagnosis, and natural history", section on 'Diagnostic evaluation'.)

Laboratory testing — Laboratory tests prior to UAE are:

●Hemoglobin/hematocrit – This should be ordered in all patient with heavy or prolonged menstrual bleeding.

●Serum creatinine, with calculation of glomerular filtration rate – This is required because renally cleared contrast is used.

Some experts also ensure that cervical cancer screening is current and perform an endometrial biopsy prior to embolization to exclude endometrial pathology [25]. While such testing is not specifically required by guidelines, it is clinically reasonable.

Pelvic imaging — The first-line imaging study to evaluate for uterine fibroids is pelvic ultrasound.

Many protocols include magnetic resonance imaging (MRI) before UAE in order to properly determine size and location and ensure that the uterine masses are consistent with uterine fibroids. In our view, in many cases, an MRI is not necessary if ultrasound provides a clear diagnosis and can identify fibroid location according to the International Federation of Gynecology and Obstetrics classification system (figure 3) [26].

MRI is superior in cases of large uteri where the whole uterus cannot be visualized with ultrasound. We order an MRI prior to UAE when the uterus is too large to evaluate reliably by ultrasound or an experienced pelvic sonologist is not available [27,28]. Furthermore, there is some evidence that an MRI before UAE may decrease procedure time. And also, an MRI might be used to assess for ovarian arterial flow and thus stratify those at highest risk for ovarian insufficiency [29-31].

While pelvic imaging can characterize a lesion as likely to be a benign fibroid, imaging generally cannot exclude occult malignancy, such as leiomyosarcoma, within a fibroid.

PREPROCEDURE PREPARATION

Informed consent — Patients with symptomatic uterine leiomyomas should be counseled about medical and surgical treatment options. (See "Abnormal uterine bleeding in nonpregnant reproductive-age patients: Management" and "Uterine fibroids (leiomyomas): Treatment overview".)

Patients should be counseled about potential complications of the procedure and about the likelihood of recurrence of fibroids or symptoms. (See 'Complications' below.)

This discussion should be documented in the medical record and on the procedure consent form.

Antibiotic prophylaxis — For patients undergoing UAE for treatment of leiomyomas, we suggest not giving prophylactic antibiotics to prevent surgical site infection.

There are no standard guidelines on prophylactic antibiotics for UAE. Policy on prophylactic antibiotics varies among clinics and in publications on UAE. This issue has not been evaluated in randomized trials.

On average, post-embolization infection prevalence is estimated to be <1 percent [10]. Pathophysiologically, infection may take longer to develop, since infection may not develop until necrosis is present. Also, submucosal fibroids may be more likely to become infected, due to exposure to ascending infection in the uterine cavity; however, this is a theoretical concern and has not been investigated.

Given the lack of evidence and the low risk of infection, routine preoperative prophylactic antibiotics are not required. The exception to this may be in patients with large submucosal fibroids, but this issue requires further study.

Antibiotic prophylaxis for gynecologic procedures is shown in the table (table 1) and discussed separately. (See "Overview of preoperative evaluation and preparation for gynecologic surgery", section on 'Surgical site infection prevention'.)

Thromboprophylaxis — Thromboprophylaxis, in general, is only applicable for intravascular procedures when a patient is at increased risk for thromboembolic disease [32].

Thromboprophylaxis is discussed in detail separately. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

PROCEDURE — UAE is a percutaneous angiographic procedure performed with video fluoroscopic imaging. UAE is performed by a trained interventional radiologist.

Procedure setting — Percutaneous transcatheter embolization procedures are typically performed under fluoroscopic guidance in the radiology suite. The duration of the procedure depends on the volume and the number of the myomas, anatomy of the vasculature, and skills of the radiologist.

Anesthesia — UAE is performed under local anesthesia (sometimes combined with epidural anesthesia or patient-controlled anesthesia for postoperative pain relief). Local anesthesia is injected at the planned puncture site in the groin. Sedation can be given if the patient wishes. Lidocaine injected into the uterine arteries during or after UAE reduced postprocedural pain and narcotic agent dose after UAE. There were more cases of incomplete necrosis when lidocaine was mixed with the particles [33].

The administration of single-dose intravenous dexamethasone as an adjunct to fentanyl-based intravenous patient-controlled anesthesia is effective in reducing inflammation and pain during the first 24 hours after UAE, although the effect is small. Dexamethasone had a positive effect on severe nausea and vomiting in the same trial and no evident side effects, thereby possibly worth considering administering [34].

Catheter placement — The patient is placed in the supine position. The Seldinger technique is used to introduce a catheter into the femoral artery (figure 4A-B) [35]. The catheter is then advanced into the uterine artery, depending upon the indication for the procedure. After subselective catheterization, diagnostic angiography of the artery is obtained to confirm proper position and look for extravasation suggestive of acute bleeding (image 1A-D).

The catheter is then moved to the contralateral uterine artery and the procedure is repeated [36,37].

Embolization — The most commonly used embolic agents for UAE are nonspherical polyvinyl alcohol (PVA) (figure 4B), spherical PVA, acrylamido PVA, tris-acryl gelatin microspheres, and polyzene-F hydrogel microspheres. No clear distinction in treatment efficacy can be made between the embolic materials. Most large randomized trials of UAE used mainly polyvinyl alcohol particles, but other materials were used in other studies [3,4,38]. A systematic review including five randomized trials and five observational comparative studies did not find one material to be associated with superior clinical outcomes (eg, fibroid devascularization, uterine and dominant fibroid volume reduction) [39-41].

The embolic material is injected and is carried by the arterial blood flow to the vessels feeding the fibroid. These vessels are preferentially occluded, since they are larger and have a higher flow than myometrial branches that do not perfuse vascular lesions like fibroids. The procedure is terminated when the fibroid blood supply is occluded but there is still sluggish flow in the uterine artery.

COMPLICATIONS — Common complications of UAE include pelvic pain, fever, and vaginal discharge, but these are self-limited in most patients. Some patients may develop ovarian insufficiency.

The most serious potential complications are introduction of embolic agents into inadvertent vessels, necrosis of the gluteus maximus or limb, or pulmonary embolism. Mortality after UAE is very rare, but there are several published case reports [42-45]. Cause of these deaths were sepsis because of necrotic myoma or pulmonary embolism after UAE.

Morbidity after UAE can be divided in periprocedural (first 24 hours), early complications (within 30 days), and late complications (beyond 30 days).

Periprocedural — Periprocedural complications are uncommon (<5 percent) and include groin hematoma, arterial thrombosis, and, infrequently, (pseudo)aneurysm [6]. Groin hematoma is managed expectantly, arterial thrombosis is treated with anticoagulants, and (pseudo)aneurysm is treated by interventional radiologist if needed or managed expectantly.

Early complications — Common early complications include fever, nausea, pain, and malaise; as a set of issues, these comprise post-embolization syndrome [6].

Patients may experience pelvic pain following UAE; postprocedural pain is typically self-limiting [46]. Pain is due to necrosis of tissue and seems to be associated with fibroid volume and is usually most severe during the first 24 hours. Pain during the first 24 hours can be managed with patient-controlled analgesia, this can then be transitioned to oral pain medications, usually nonsteroidal anti-inflammatory drugs [47]. In a small randomized controlled trial, dexamethasone (10 mg intravenous) was found to be effective in reducing inflammation and pain after UAE [34]. Future studies are required to validate these findings.

If severe pain persists, readmission for pain control may be necessary (up to 9 percent of cases) [6]. A recurrence of severe pain after a period of milder pain may indicate fibroid expulsion and warrants evaluation. UAE results in more readmissions than hysterectomy or myomectomy. In a meta-analysis of seven randomized trials, UAE compared with hysterectomy resulted in a significantly higher rate of unscheduled visits or readmissions within six weeks (odds ratio [OR] 2.79, 95% CI 1.41-5.49, one trial, 157 subjects [46]) [7].

Another complication that is also relatively common (16 to 20 percent) is vaginal discharge [48]. This can last for months and is usually self-limiting, provided that the discharge is not purulent and fever is absent.

If patients present with purulent vaginal discharge after UAE in combination with fever, they should be evaluated for pelvic or systemic infection with vital signs, physical examination, a white blood cell count, C-reactive protein, culture of vaginal or cervical discharge, and pelvic ultrasound [32]. Ultrasound can show a prolapsing fibroid or evidence of pelvic inflammatory disease. Magnetic resonance imaging is used in rare cases where ultrasound findings are inconclusive. Blood cultures should be ordered if systemic infection is suspected, but we have rarely seen a patient with positive blood cultures after UAE.

If examination or laboratory testing is consistent with infection, we treat with antibiotics. Endometrial infection occurs in 0.5 percent of cases (mostly with submucosal fibroids) [32]. The antibiotic treatment regimen is the same as in pelvic inflammatory disease (see "Pelvic inflammatory disease: Treatment in adults and adolescents"), unless the cultures find specific bacteria.

Persistent vaginal discharge combined with abdominal tenderness or pain, but without fever, may be due to a submucosal intracavity necrotic fibroid being expelled through the cervix into the vagina. Vaginal expulsion of a fibroid (or fibroid tissue) is a relatively common phenomenon, and in general it can be managed expectantly, but sometimes it is necessary to perform a hysteroscopy to remove the fibroid [32].

Late complications — Ovarian insufficiency following UAE occurs more frequently in patients older than 45 years, and patients may develop menopausal symptoms and/or amenorrhea. Arterial flow to the ovary is likely to be transiently occluded during UAE but may be re-established in the longer term. UAE appears to be unlikely to decrease ovarian reserve in patients younger than 40 years [49,50].

In the embolization versus hysterectomy randomized trial (EMMY), 156 premenopausal patients were treated with either UAE or hysterectomy [51]. At 24 months, menopausal symptom scores and anti-müllerian hormone (AMH) levels were similar between groups, but the UAE group had lower AMH values than age-adjusted levels in the general population. In a subsequent randomized trial including 254 patients with symptomatic fibroids undergoing UAE or myomectomy, differences in ovarian reserve were similar between groups through the first year postprocedure [52]. Larger studies are needed to confirm these findings.

FOLLOW-UP — We see patients for a follow-up visit several weeks after UAE. Patients are counseled about the signs and symptoms of minor and major complications. In case of pain that does not respond to nonsteroidal anti-inflammatory drugs, fever, or foul-smelling vaginal discharge, the patient is advised to contact the clinician for evaluation for complications [18].

Follow-up imaging studies are not done routinely but performed as needed based on persistent or recurrent symptoms or concern about complications. Decisions regarding reintervention are made based upon symptoms (eg, good response in terms of volume reduction but unchanged heavy menstrual bleeding might result in reintervention, whereas the opposite situation might not).

OUTCOMES

Efficacy — The efficacy of UAE is determined by symptom relief for patients with uterine fibroids. Major symptoms are heavy menstrual bleeding, dysmenorrhea, pelvic pain or pressure, and other bulk-related symptoms:

●Heavy menstrual bleeding – It has been shown that most patients (73 to 90 percent) reported improvement or disappearance of heavy menstrual bleeding symptoms up to 10 years after treatment [8,53]. In the embolization versus hysterectomy randomized trial (EMMY), 156 premenopausal patients were treated with either UAE or hysterectomy and 156 underwent treatment [3,8,54]. At two years, 62 percent of patients in the UAE group reported that menorrhagia had completely resolved. At five years, 83 percent of patients in the UAE group reported no menorrhagia or great or moderate improvement. The subsequent cumulative hysterectomy rate was 24 percent at two years, 28 percent at five years, and 35 percent at 10 years. Secondary hysterectomies were performed for persisting symptoms in all cases except one (for prolapse).

●Pelvic pain or dysmenorrhea – The effect of UAE on lower abdominal pain or dysmenorrhea has also been described and shows an improvement in up to 80 percent of patients. In the EMMY trial, there was a comparable proportion of patients in the UAE compared with hysterectomy group (85 versus 78 percent) who reported at least moderate improvement in lower abdominal pain at two years [3]. The Ontario Uterine Fibroid Embolization Trial was a multicenter prospective study that reported improvement in dysmenorrhea in 77 percent of 538 patients undergoing bilateral UAE [55].

●Pelvic pressure or bulk-related symptoms – The effect of UAE on bulk and pressure complaints is less well studied, but in large cohort studies, up to 90 percent of patients reported improved bulk complaints [9,10]. In the EMMY trial, there were comparable rates of improvement in bulk-related symptoms in the UAE and hysterectomy groups at two years (66 versus 69 percent) [3].

Many studies have evaluated patient satisfaction rather than relief of specific symptoms. In a meta-analysis of seven randomized trials including 793 patients, there was no significant difference in the pooled data in patient satisfaction at two or five years with UAE compared with hysterectomy or myomectomy, although there was a wide variation across studies ranging from 41 percent lower to 48 percent higher [7]. Another systematic review comparing UAE and surgery showed that, even after five years of follow-up, health-related quality of life was significantly higher than baseline, without differences between the study groups [6]. In the EMMY trial, at 10 years, generic health-related quality of life remained stable, without differences between both groups [8]. Satisfaction in both groups remained comparable. The majority of patients declared being (very) satisfied about the received treatment (UAE: 78 percent versus hysterectomy 87 percent).

Need for subsequent treatment — Subsequent hysterectomy for failure or recurrence of symptoms after UAE was reported to be 27 percent (51 of 187) at five years in a meta-analysis of four randomized trials [6]. A meta-analysis of seven randomized trials found a significantly higher rate of further intervention within two years for UAE than myomectomy or hysterectomy (odds ratio [OR] 3.72, 95% CI 2.28-6.04) [7].

Other possible subsequent procedures to treat heavy menstrual bleeding after UAE include dilation and curettage, hysteroscopy, endometrial ablation, myomectomy (5 percent), or repeat UAE [6,56]. In the EMMY trial, at five years after treatment, 23 secondary hysterectomies and 5 other reinterventions were reported for heavy menstrual bleeding (curettage, endometrium ablation, or myomectomy) in the 81 UAE patients, whereas they reported 8 reinterventions in the 75 hysterectomy patients [4]. Another study reported 28 reinterventions (not specified) in the 106 UAE patients and 1 in the 50 hysterectomy patients. In the UAE group, 82.7 percent of the participants reported to be symptom-free or to experience improvement [5].

Uterine artery embolization versus surgery — Although UAE has several short-term advantages to surgery, the long-term advantages are less clear.

In meta-analyses of randomized trials comparing UAE with surgery (hysterectomy and myomectomy [7]; hysterectomy, myomectomy, laparoscopic uterine artery occlusion [57]), UAE resulted in:

●Faster resumption of daily activities and return to work [7].

●Lower rates of blood transfusion (OR 0.07, 95% CI 0.01-0.52) [7].

●Lower risks of major complications (risk ratio [RR] 0.45, 95% CI 0.22-0.95) [57].

●Higher risks of minor complications (RR 1.65, 95% CI 1.32-2.06) [57].

●Higher rates of reintervention after two years (83/436 versus 16/355 patients, RR 3.7) and five years (56/171 versus 9/118 patients, RR 5.0) [57]. In the embolization versus hysterectomy randomized trial (EMMY), which was not included in the analysis, at 10 years, 28 of 81 patients (35 percent) required secondary hysterectomy [8].

Quality of life was not assessed in the analyses, but in a subsequent randomized trial of 254 patients, quality of life and symptom severity were less favorable after UAE compared with myomectomy (abdominal, laparoscopic, or hysteroscopic); the magnitude of improvement on health-related questionnaires, evaluating quality of life and symptom severity two years postoperatively, was lower in the UAE group (mean differences of 8.0 and -3.8 points, respectively) [58]. While overall symptom severity was higher in the UAE group, both groups demonstrated a substantial improvement of symptoms compared with baseline.

Uterine artery embolization versus other minimally invasive treatments — UAE is the best studied minimally invasive treatment option for fibroids. Other minimally invasive treatments have emerged over the last few years with positive outcomes in case series and cohorts. There are few comparative studies, but some are starting to emerge in the literature [59].

A meta-analysis of uterus-sparing options for fibroids included 85 studies (8 were randomized trials; 14 studies compared between different procedures) with over 17,000 participants [60]. The risk of reintervention after 60 months of follow-up for each method was: UAE (14.4 percent), high intensity focused ultrasound (using localization with magnetic resonance imaging [MRI] or ultrasound; 53.9 percent), myomectomy (12.2 percent), and hysteroscopy (7 percent). All methods were associated in improved quality of life, but high intensity focused ultrasound showed the lowest degree of improvement.

A systematic review evaluating UAE, MRI-guided focused ultrasound (MRgFUS), and radiofrequency ablation (RFA) included 81 observational studies; only one study directly compared two modalities [59,61]. Pooled data for each modality showed the following mean fibroid volume reduction at 12 months: UAE (66 percent), MRgFUS (28 percent), and RFA (75 percent).

UAE was compared with MRgFUS in the Fibroid Interventions: Reducing Symptoms Today and Tomorrow study (FIRSTT); the study combined analysis of randomized trial data in 57 patients and observational data in 34 (participants who refused randomization) [62]. MRgFUS compared with UAE resulted in a higher rate of reintervention for symptomatic fibroids (30 versus 12.5 percent) within three years. Reintervention was more likely when treatments occurred at younger ages and in patients with higher pretreatment anti-müllerian hormone (AMH) levels. AMH levels at 24 months were lower in the UAE group. Both treatment arms improved in quality of life scores and pain, although the effect was larger in the UAE group. The decrease in AMH levels reconfirms our caution regarding use of UAE in patients who desire future fertility.

Observational studies that directly compared UAE with MRgFUS have also found a lower reintervention rate with UAE, consistent with the FIRSTT study [63,64].

UAE was compared with uterine artery occlusion in several randomized comparisons. First, two pilot studies were performed with 20 and 14 patients who were randomized to either UAE or uterine artery occlusion [65,66]. These pilots demonstrated good clinical (short-term) results with less pain after the occlusion technique. Thereafter, two larger trials were done [67,68]. In one randomized trial (n = 69), satisfaction with menstrual blood loss was comparable between the two treatments but tended to remain improved more than 12 months after UAE [67]. Another trial (n = 66) compared UAE with uterine artery occlusion and found that UAE was superior in terms of recurrence rate (48 versus 17 percent) and volume reduction (51 versus 33 percent) after 48 months of follow-up [68].

UAE has also been compared with microwave ablation (MWA). In a randomized superiority trial including 34 patients with symptomatic uterine fibroids, treatment with MWA was not superior to UAE (fibroid volume reduction: 42 versus 62 percent, respectively) [69]. Additional studies with larger cohorts are needed to confirm these findings.

REPRODUCTIVE OUTCOMES

Pregnancy — UAE may be associated with an increase in some adverse obstetric outcomes (eg, miscarriage, cesarean birth), but further study is needed.

A meta-analysis that included 227 pregnancies after UAE from nine mainly observational studies (there was one randomized trial) compared these with pregnancies in controls from other studies with fibroids matched for age and fibroid location [19]. Pregnancies after UAE had higher miscarriage rates (35 versus 17 percent, odds ratio [OR] 2.8, 95% CI 2.0-3.8) and were more likely to have a cesarean birth (66 versus 49 percent, OR 2.1, 95% CI 1.4-2.9) and postpartum hemorrhage (14 versus 3 percent, OR 6.4, 95% CI 3.5-11.7). UAE and control pregnancies showed similar rates of preterm birth (14 versus 16 percent, respectively) and intrauterine growth restriction; however, the study lacked sufficient statistical power to detect a difference in these outcomes.

Higher rates of preterm birth have been described. In a retrospective study including 109 patients with a live birth after UAE, preterm birth occurred in 23 patients (32 percent); the average age at birth for those delivering preterm was 35 (±2.8) weeks gestation [70].

In a subsequent randomized trial including eight pregnancies within four years of UAE, five resulted in a livebirth, two in pregnancy loss, and one pregnancy was terminated [52]. These numbers are too small to draw any conclusions on the effect of UAE on pregnancy outcomes.

Fertility — In general, there are few studies of the impact of UAE on fertility as most patients are counseled not to become pregnant after UAE due to concerns about adverse obstetric outcomes. (See 'Pregnancy' above.)

Available data suggest a modest to minimal negative impact on fertility. In one randomized trial including 121 patients with fibroids who desired future fertility, those undergoing UAE compared with myomectomy had lower rates of pregnancy (50 versus 78 percent); patients were followed for a mean of 25 months [20].

Fibroids themselves, particularly those that impinge upon the endometrium, may affect fertility by interfering with implantation over the myoma site, rapidly distending the uterus in early pregnancy, or impairing uterine contractility. This is discussed in detail separately. (See "Uterine fibroids (leiomyomas): Treatment overview", section on 'Patients desiring fertility'.)

The effect of UAE on ovarian reserve is discussed above. (See 'Late complications' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Uterine fibroids (leiomyomas)" and "Society guideline links: Gynecologic surgery".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Beyond the Basics topics (see "Patient education: Uterine fibroids (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Definition – Uterine artery embolization (UAE) is a minimally invasive treatment for uterine fibroids (leiomyomas). The procedure is a percutaneous angiographic procedure performed with video fluoroscopic imaging with injection of embolic agents into the uterine artery (figure 4A and figure 4B). (See 'Introduction' above.)

●Patient selection

•Candidates – Ideal candidates for UAE include patients with heavy menstrual bleeding or dysmenorrhea caused by intramural fibroids, who are premenopausal, and who have no desire for future pregnancy. If pelvic pain/pressure or bulk-related symptoms are the only symptom, efficacy of UAE is questionable. (See 'Indications' above.)

•Contraindications – Absolute contraindications of UAE including patients who are pregnant, have pelvic inflammatory disease or uterine malignancy, or with asymptomatic fibroids.

Relative contraindications include:

-Future fertility – We suggest not performing UAE in patients who desire future pregnancy (Grade 1C). However, UAE may be reasonable in patients with severe anemia or symptoms associated with fibroids, those who have failed conservative measure and have contraindications to surgery, or those who consent to UAE within an approved research protocol. Patients should be counseled about the potential risks of UAE to a future pregnancy. (See 'Contraindications' above and 'Reproductive outcomes' above.)

-Pedunculated fibroids – Subserosal or submucosal fibroids that are pedunculated and have a narrow stalk (stalk <50 percent in diameter in comparison with the largest diameter fibroid) are considered a relative contraindication to UAE. (See 'Contraindications' above.)

-Large fibroids – The volume of necrosis after UAE in a large fibroid uterus can be substantial with a proportionate level of postprocedural pain. However, no clear threshold for the size of the uterus or size or number of fibroids has been established as a contraindication. (See 'Contraindications' above.)

●Imaging – The first-line imaging study to evaluate for uterine fibroids is pelvic ultrasound. Many protocols include magnetic resonance imaging before UAE in order to properly determine size and location and ensure that the uterine masses are consistent with uterine fibroids. (See 'Pelvic imaging' above.)

●Efficacy – Most patients (73 to 90 percent) report improvement or disappearance of heavy menstrual bleeding symptoms up to ten years after treatment. Lower abdominal pain or dysmenorrhea shows an improvement in up to 80 percent of patients. Approximately 28 percent of patients undergo hysterectomy within five years after UAE. (See 'Efficacy' above and 'Need for subsequent treatment' above.)

●Complications – Common complications of UAE include pelvic pain, fever, and vaginal discharge, but these are self-limiting in most patients. Some patients may develop ovarian insufficiency. The most serious potential complications are introduction of embolic agents into inadvertent vessels, necrosis of the gluteus maximus or limb, or pulmonary embolism. (See 'Complications' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Ducksoo Kim, MD, and Stephen D Baer, MD, who contributed to earlier versions of this topic review.