Fibroids and Back Pain: The Pelvic Symptom Women Don’t Connect to Their Uterus

Lower back pain is one of the most common complaints in medicine: the kind of symptom that sends millions of Americans to orthopedists, chiropractors, physical therapists, and pain management specialists every year. The usual suspects are investigated: disc disease, facet arthropathy, muscle strain, sciatica. Imaging is ordered. Treatment is prescribed. And for a significant number of women, nothing adequately explains or resolves the pain.

Here’s the connection that’s frequently missed: the uterus sits directly in front of the sacrum, the base of the spine. When uterine fibroids enlarge, particularly posterior fibroids growing toward the back of the pelvis, they can press against the sacrum, the sacral nerve plexus, and the lumbar nerve roots. The result is lower back pain that is genuinely pelvic in origin but that mimics musculoskeletal back pain closely enough to be misdiagnosed for months or years.

At Surgical Associates, we routinely see women whose back pain is the symptom that finally brings them to a fibroid evaluation, often after an unsuccessful journey through other specialties. Understanding this connection can save you from ineffective treatments aimed at the wrong source.

How Fibroids Cause Back Pain: The Anatomy

To understand why a uterine growth can cause back pain, you need to understand the pelvic anatomy.

The uterus and spine are neighbors. The uterus sits in the center of the pelvis, anterior to (in front of) the sacrum and coccyx. The sacral nerve plexus, a network of nerves emerging from the lower spinal cord that provides sensation and motor function to the pelvis, buttocks, and legs, runs along the anterior surface of the sacrum. The ureters (tubes connecting kidneys to bladder) run alongside the uterus. The rectum sits directly behind.

In a normal-sized uterus, there’s adequate space between these structures. When fibroids enlarge the uterus, sometimes to the size of a grapefruit, a cantaloupe, or larger, the pelvic anatomy becomes crowded. Structures that normally have room to function independently become compressed.

Posterior fibroids are the primary culprits. Fibroids growing on the posterior (back) wall of the uterus are positioned directly adjacent to the sacrum and sacral nerves. Even relatively modest posterior fibroids, 5 to 7 centimeters, can exert enough pressure on the sacrum to cause persistent, deep aching in the lower back. Larger posterior fibroids can compress the sacral nerve plexus itself, producing symptoms that resemble sciatica: pain, tingling, or numbness radiating into the buttocks, hips, or down the legs.

Subserosal fibroids add to the problem. Fibroids growing on the outer surface of the uterus (subserosal) project outward and can press on adjacent structures regardless of their specific position. A large subserosal fibroid on the posterior wall creates a double effect: the fibroid itself pushes backward toward the spine while the overall uterine enlargement fills the pelvic cavity.

The symptoms this produces include a deep, dull ache in the lower back that may be constant or cyclical with menstruation, pain that worsens during periods (as the uterus contracts around and against the fibroid), sciatica-like radiating pain into the buttocks or legs, a sensation of pelvic heaviness or pressure, difficulty finding a comfortable position when lying on the back, and pain that is not reliably reproduced by specific back movements (bending, twisting), because the source isn’t musculoskeletal.

The Diagnostic Disconnect: Why This Gets Missed

The diagnostic challenge is that fibroid-related back pain feels like musculoskeletal back pain. Women and their physicians naturally look for musculoskeletal explanations first. A reasonable workup for new lower back pain might include physical examination focusing on the spine, lumbar X-rays or MRI (which show the spine but not the uterus), physical therapy referral, muscle relaxants or anti-inflammatory medications, and epidural steroid injections if disc disease is suspected.

If none of these reveal a clear spinal pathology, or if treatment aimed at the spine doesn’t provide relief, the workup often reaches an unsatisfying conclusion: “nonspecific lower back pain.” The patient is told to continue PT, manage with medications, and accept a degree of chronic discomfort.

What’s missing from this workup is a pelvic evaluation. Unless someone asks about menstrual symptoms, performs a pelvic exam, or orders pelvic imaging, the fibroids sitting three inches from the spine go undetected.

Red flags that back pain may be fibroid-related: The pain worsens around menstruation. You also have heavy periods, prolonged periods, or intermenstrual bleeding. You’ve noticed increased pelvic pressure, bloating, or urinary frequency. Standard back treatments haven’t provided expected improvement. You have a known fibroid diagnosis but haven’t discussed your back pain with your gynecologist or interventional radiologist.

The diagnostic solution: A pelvic MRI. MRI is the gold standard for fibroid evaluation: it reveals the number, size, and location of every fibroid, including posterior fibroids positioned against the sacrum. If you have chronic lower back pain plus any of the red flags above, asking for a pelvic MRI is a reasonable and potentially diagnosis-changing step.

How UFE Addresses Fibroid-Related Back Pain

The logic is straightforward: if the back pain is caused by fibroid-related pressure on the sacrum and pelvic nerves, then shrinking the fibroids will reduce the pressure and relieve the pain.

Uterine fibroid embolization blocks the blood supply to fibroids, causing them to shrink progressively over weeks and months. As fibroid volume decreases, studies show average volume reductions of 40–60% at six months, the mass effect on posterior structures decreases proportionally.

Patients with fibroid-related back pain typically report improvement following a timeline that mirrors fibroid shrinkage. Initial relief may be noticed within the first few weeks as the acute inflammatory response to embolization resolves. Progressive improvement continues over 3–6 months as fibroids continue to shrink and pressure on the sacrum and nerves decreases. By six months to one year, most patients have experienced the full benefit.

This is the same principle that drives symptom improvement in fibroid-related bladder symptoms and fibroid-related constipation: shrink the mass, relieve the compression.

The Comprehensive Symptom Picture

Back pain from fibroids rarely occurs in isolation. Most women with posterior fibroids large enough to cause back pain also have other fibroid symptoms: they just may not have connected them all to a single cause.

Consider whether you also experience heavy menstrual bleeding (the most common fibroid symptom), prolonged periods lasting more than 7 days, pelvic pressure or a sensation of fullness in the lower abdomen, frequent urination or urgency (from anterior fibroids pressing on the bladder), constipation (from fibroids pressing on the rectum), bloating or abdominal distension, pain during intercourse (dyspareunia), or fatigue from iron-deficiency anemia caused by chronic heavy bleeding.

If you have back pain plus two or more of these symptoms, the probability that fibroids are contributing rises significantly. A comprehensive evaluation at SACMD includes assessment of all fibroid-related symptoms, not just the one that brought you in.

What to Ask Your Doctor

If you suspect your back pain may be fibroid-related, here are the questions to raise:

“Could fibroids be contributing to my lower back pain? Has a pelvic exam or pelvic imaging been done?” “I have heavy periods and lower back pain. Could these be connected?” “My lumbar MRI didn’t show a clear spinal cause for my pain. Should we consider a pelvic MRI?” “If fibroids are confirmed, am I a candidate for UFE?”

FAQ Schema:

Q: Can fibroids cause lower back pain?
A: Yes. Posterior fibroids, those growing toward the back of the pelvis, can press against the sacrum, lumbar spine, and sacral nerve plexus, causing deep lower back pain, sciatica-like symptoms, and pelvic heaviness. The larger the fibroid and the more posterior its position, the more likely it is to cause back symptoms.
Q: How do I know if my back pain is from fibroids?
A: Clues include back pain that’s cyclical (worsening around menstruation), co-existing with heavy periods or other fibroid symptoms, not responding to standard musculoskeletal treatments (PT, muscle relaxants, steroid injections), and worsening over time as fibroids grow. A pelvic MRI can confirm whether posterior fibroids are compressing the sacrum or nerve roots.
Q: Will UFE help my fibroid-related back pain?
A: As UFE shrinks fibroids, the physical pressure they exert on the sacrum and nerves decreases proportionally. Patients with fibroid-related back pain typically report progressive improvement over the 3–6 months following UFE as fibroid volume reduces.
Q: Could my back pain be from both fibroids and a spine problem?
A: Yes. It’s possible to have both musculoskeletal back pain and fibroid-related back pain simultaneously. This is why imaging matters: a pelvic MRI evaluates the fibroids while a lumbar MRI evaluates the spine. Both may be needed for a complete picture.
Q: What other pelvic symptoms should make me think of fibroids?
A: In addition to back pain, fibroids can cause heavy menstrual bleeding, pelvic pressure or fullness, urinary frequency or urgency, constipation, bloating, and pain during intercourse. Many women have several of these symptoms without realizing they share a common cause.

The Bottom Line

Lower back pain that doesn’t respond to standard musculoskeletal treatments may not be musculoskeletal at all. For women with uterine fibroids, particularly posterior fibroids positioned against the sacrum, the pain source may be three inches away from where everyone has been looking.

If you have chronic lower back pain plus heavy periods, pelvic pressure, or any of the other fibroid symptoms described above, a pelvic MRI can determine whether fibroids are part of the picture. And if they are, UFE can shrink them without surgery, relieve the pressure, and potentially resolve a back pain problem that no amount of physical therapy or spinal injections could address, because the source was never in the spine.

Schedule a consultation: Call (240) 427-1630 or visit www.sacmd.com


Disclaimer: This article is for informational purposes only and does not constitute medical advice. Back pain has many potential causes. A comprehensive evaluation should consider both musculoskeletal and pelvic sources.

References:

  1. ACOG. Uterine Leiomyomas (Fibroids): Symptoms and Diagnosis. Practice Bulletin.
  2. Mayo Clinic. Uterine Fibroids: Symptoms and Causes. mayoclinic.org.
  3. Cleveland Clinic. Fibroids and Pelvic Pain. clevelandclinic.org.
  4. NIH/NICHD. Uterine Fibroids: Symptoms. nichd.nih.gov.
  5. PubMed. Mass effect of uterine leiomyomas on adjacent pelvic structures.