Fibroids can cause leg pain, though most people with fibroids never experience it. When a fibroid grows large enough to press against nerves or blood vessels in the pelvis, the effects can radiate down into the thighs, groin, knees, and even lower. The connection is well documented in medical case reports, and the two main pathways involve direct nerve compression and obstruction of blood flow through the pelvic veins. Because leg pain is not typically listed among the “classic” fibroid symptoms, it often gets attributed to orthopedic problems or spinal issues before anyone thinks to check the uterus.
How a Fibroid Can Press on Pelvic Nerves
The pelvis is a crowded space. The uterus sits near the lumbar plexus, a web of nerves that branches out from the lower spine and runs through the pelvis before sending signals down each leg. When a fibroid grows large, especially one on the back wall of the uterus, it can push directly into these nerve bundles. The result is pain, numbness, or weakness in areas that seem completely unrelated to the uterus.
In one well-documented case, a 32-year-old woman showed up to the emergency room with severe groin and knee pain and could not walk on her own. She had been experiencing numbness along the inner thigh and episodes of her knee buckling for months. Imaging revealed a fibroid roughly 12.5 by 13 centimeters that was compressing the iliac veins and sitting right against multiple branches of the lumbar plexus, including both obturator nerves. After ruling out every other possible explanation, her doctors concluded the fibroid’s sheer mass was the cause.1PubMed Central. Uterine Fibroid-Induced Compressive Neuropathy of Lumbar Plexus and Obturator Nerve
The obturator nerve specifically controls sensation along the inner thigh and helps stabilize the hip and knee. When a fibroid leans into it, you can feel pain in the groin that shoots toward the knee, numbness on the inside of the thigh, or a strange instability when walking. These symptoms can worsen during menstruation, when hormone fluctuations may cause fibroids to swell slightly, increasing the pressure on nearby nerves.
Not every fibroid creates this kind of problem. Location and size both matter. A small fibroid on the inner lining of the uterus might cause heavy bleeding but would never reach the pelvic nerves. It is the large, posteriorly positioned fibroids, ones growing on the outer back wall of the uterus and extending toward the spine and pelvic sidewall, that are most likely to encroach on nerve territory.
When Fibroids Block Blood Flow in the Legs
The second way fibroids cause leg symptoms is by pressing on the veins that carry blood back from the legs to the heart. The iliac veins, which run through the pelvis, are particularly vulnerable. A large fibroid sitting on or near these veins can partially or fully obstruct them, slowing blood flow and creating the conditions for a blood clot to form.
This is not a theoretical risk. An expert review of the medical literature found that the relationship between fibroids and blood clots is mainly attributed to physical compression of pelvic veins, particularly the iliac veins, leading to blood pooling and clot formation.2PubMed Central. Uterine Fibroids and Their Association with Acute and Chronic Venous Thromboembolic Disease-An Expert Review of the Literature In clinical terms, the fibroid creates a situation similar to May-Thurner syndrome, a condition where the left iliac vein gets pinched between an artery and the spine. The fibroid essentially mimics that anatomical problem by squeezing the vein from the outside.3Hong Kong Medical Journal. Multidisciplinary staged management of iliofemoral venous thrombosis caused by huge uterine fibroid: a case report
When a deep vein thrombosis forms in the leg because of this compression, the symptoms are different from nerve-related leg pain. You are more likely to see swelling in one leg, a feeling of heaviness or tightness, warmth in the affected area, and a dull ache that worsens when standing or walking. One reported case involved a 47-year-old woman who developed progressive swelling and pain in her left leg. Doctors diagnosed extensive clotting in the veins running from her pelvis down through her thigh, and the underlying cause was an enlarged fibroid uterus pressing on the left common iliac vein.4PubMed Central. Extensive Iliofemoral Deep Vein Thrombosis Secondary to Uterine Leiomyoma-Induced Iliac Vein Compression: A Case Report
Multiple case reports describe a similar pattern: a bulky fibroid uterus compressing the left iliac vein and triggering a clotting event that presents as sudden leg pain and swelling.5NSUWorks. Venous Compression Secondary to Uterine Leiomyomas: A Unique Clinical Presentation The left side appears more commonly affected because of the pelvis’s natural anatomy: the left iliac vein already passes through a tighter space, making it more susceptible to external pressure.
Size Matters More Than You Might Think
Not all fibroids carry the same risk for leg problems. Small fibroids, even clusters of them, rarely grow large enough to reach the nerves or veins that serve the legs. The cases where leg symptoms develop almost always involve fibroids that have grown quite large, often exceeding ten centimeters in diameter.
A study that looked at the relationship between uterine size and deep vein thrombosis found a clear threshold effect. When the uterus weighed less than about 1,000 grams, the rate of DVT among patients was around 3 percent. But when the uterus weighed 1,000 grams or more, roughly the size of an adult’s head on a pelvic exam, the DVT rate jumped to about 11.5 percent.6PubMed. Deep-vein thrombosis is associated with large uterine fibroids That is nearly a fourfold difference. The implication is straightforward: the bigger the fibroid burden, the more pressure on the surrounding anatomy, and the higher the risk that blood flow through the pelvis gets disrupted enough to cause problems downstream in the leg.
For nerve-related leg pain, the threshold is harder to pin down because nerve compression depends heavily on where the fibroid sits, not just how big it is. A fibroid that happens to grow directly against the obturator nerve could potentially cause symptoms at a smaller size than one sitting further away. Still, the published cases almost universally describe fibroids in the range of 10 to 15 centimeters or larger.
Why Fibroid-Related Leg Pain Gets Misdiagnosed
If you went to a doctor complaining of knee pain, groin pain, or numbness running down your inner thigh, the first thing most clinicians would think about is a back problem, a hip issue, or a musculoskeletal injury. That is a reasonable starting point, because those are far more common causes. But it also means that a pelvic mass gets overlooked until the orthopedic workup comes back empty.
The case of the 32-year-old woman described earlier is a good illustration. Before anyone connected her symptoms to the fibroid, her imaging workup explored several other possibilities: mild spinal stenosis at L4-L5, a hip joint abnormality, and a benign bone lesion near the femur. None of those findings explained her level of pain and disability. It was only after systematically ruling out the alternatives that the large posterior fibroid compressing her lumbar plexus was identified as the likely culprit.7PubMed Central. Uterine Fibroid-Induced Compressive Neuropathy of Lumbar Plexus and Obturator Nerve – Section: Case Description
The case report’s authors made a point worth underscoring: when no other cause of nerve-related leg symptoms can be identified, a pelvic mass should be considered as a leading possibility. This is especially true if you already know you have fibroids, or if the leg symptoms follow a menstrual pattern, getting worse around your period and improving afterward. That cyclical worsening is a strong hint that something hormonally responsive, like a fibroid, may be involved.
The diagnostic delay is not purely a physician-awareness problem. Many women with large fibroids have gotten so used to their pelvic symptoms that they do not connect new leg pain to a condition they have been managing for years. The fibroid may have been growing slowly, crossing the size threshold for nerve or vein compression gradually, with leg symptoms building so incrementally that they seem like a separate issue entirely.
What the Leg Symptoms Actually Feel Like
The character of leg pain caused by fibroids depends on which pathway is involved, and recognizing the difference matters because one of them is a medical emergency.
Nerve compression from fibroids tends to produce:
- Radiating pain: sharp or burning pain that starts in the groin or hip area and travels down the inner thigh, sometimes reaching the knee
- Numbness or tingling: a pins-and-needles sensation along the inner thigh, similar to what you might feel with a pinched nerve in the back
- Leg weakness: difficulty with movements that require hip stability, such as climbing stairs, getting out of a car, or simply walking
- Knee instability: unexpected buckling of the knee, which can be alarming and increase fall risk
Vascular compression, on the other hand, tends to produce symptoms centered on one leg and related to swelling rather than nerve function:
- Unilateral swelling: one leg, usually the left, becomes noticeably larger than the other
- Heaviness and aching: a deep, dull pain that gets worse with standing and improves when lying down
- Skin changes: redness, warmth, or a tight feeling in the swollen leg
- Sudden onset: unlike the gradual nerve symptoms, DVT-related leg swelling and pain can develop over hours to days
If you develop sudden swelling and pain in one leg, especially alongside known fibroids, this warrants urgent medical evaluation. A blood clot in the deep veins of the leg can break loose and travel to the lungs, which is life-threatening. One case report described exactly this scenario: a large fibroid caused DVT that progressed to a pulmonary embolism, requiring emergency clot removal and eventual hysterectomy.8PubMed Central. Large uterine fibroid causing DVT and PE: Successful management with mechanical aspiration thrombectomy and hysterectomy
Treatment Options and What to Expect
When leg pain is traced back to fibroids, the treatment goal is reducing the size of the fibroid or removing it to relieve the pressure on the affected nerve or vein. Several approaches exist, and which one makes sense depends on the severity of symptoms, whether you want to preserve your fertility, and how large the fibroid has grown.
Uterine artery embolization is a minimally invasive procedure where tiny particles are injected into the arteries feeding the fibroid, cutting off its blood supply and causing it to shrink. In a clinical trial of this approach, the dominant fibroid shrank by about 42 percent in volume, and patients reported substantial improvement in a range of symptoms.9Elsevier / PubMed Central. The Ontario Uterine Fibroid Embolization Trial. Part 2. Uterine fibroid reduction and symptom relief after uterine artery embolization for fibroids Whether that degree of shrinkage is enough to relieve nerve or vein compression depends on where the fibroid sits and how much room the affected structures need. A 42 percent reduction in a 13-centimeter fibroid still leaves a sizable mass.
Myomectomy, the surgical removal of the fibroid while preserving the uterus, is another option. For posteriorly positioned fibroids pressing on pelvic nerves, this can provide complete relief if the surgeon can access and remove the growth without damaging the surrounding structures. In the case of the patient with obturator nerve compression, the fibroid was removed using a robotic-assisted laparoscopic approach.1PubMed Central. Uterine Fibroid-Induced Compressive Neuropathy of Lumbar Plexus and Obturator Nerve
Hysterectomy, removing the uterus entirely, remains the definitive treatment for fibroids and is sometimes the most practical option when fibroids are very large, multiple, or causing dangerous complications like DVT. For someone who has already developed a blood clot because of fibroid-related vein compression, the treatment plan typically involves addressing the clot first with blood thinners or clot removal, then dealing with the fibroid to prevent recurrence.
Hormonal therapies, such as GnRH agonists, can temporarily shrink fibroids and may be used as a bridge before surgery. They are not a long-term solution because fibroids tend to regrow once the medication is stopped, but they can reduce the size enough to make surgery easier or provide short-term symptom relief.
Other Pelvic Conditions That Mimic Fibroid-Related Leg Pain
Fibroids are not the only pelvic condition that can send pain into the legs. Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, can also affect pelvic nerves and cause radiating leg pain. Research using animal models has shown that endometrial cysts can grow directly onto and around nerves in the pelvis, forming connections that include active nerve fibers running between the cyst tissue and the nerve itself, along with significant immune cell activity.10PubMed Central. A Model for Radiating Leg Pain of Endometriosis The mechanism is different from fibroid-related compression; endometriosis can essentially grow into nerves, whereas fibroids push against them from the outside. But the leg symptoms can look very similar to the patient.
Ovarian cysts large enough to press on pelvic structures can occasionally produce similar symptoms, as can pelvic tumors of other types. And of course, true orthopedic problems, lumbar disc herniations, hip arthritis, piriformis syndrome, are far more common causes of leg pain in the general population. The key clue that pushes clinicians toward considering a pelvic cause is when the standard orthopedic and spinal evaluations fail to explain the symptoms, or when the leg pain has a clear relationship to the menstrual cycle.
When to Bring Up Fibroids With Your Doctor
If you have been diagnosed with fibroids and you develop new leg symptoms, especially pain along the inner thigh or groin, numbness in the leg, knee instability, or sudden one-sided leg swelling, it is worth mentioning your fibroids to whatever specialist you see first. Even if you are at an orthopedist or an emergency room for what seems like a musculoskeletal complaint, the fibroid history is relevant information that could change the diagnostic approach.
Conversely, if you have unexplained leg pain with the features described above, particularly if it worsens around your period, and you have not had a recent pelvic exam or imaging, it may be worth getting one. Fibroids are extremely common and are often present long before they are diagnosed. A large fibroid sitting silently in the pelvis could be the missing piece in an otherwise puzzling leg-pain workup.
The central takeaway from the published case literature is that clinicians and patients alike should keep pelvic masses on the list of possible explanations when leg pain does not have an obvious orthopedic or spinal source. The connection between the uterus and the legs runs through shared anatomy that is easy to forget about until something in the pelvis grows large enough to make its presence felt far from where it started.