Adenomyosis vs. Endometriosis: Are They Different or Related?

Too often you first hear the word adenomyosis after years of being told your pain or bleeding is “normal,” or after a scan that mentions fibroids, a “globular uterus,” or “possible endometriosis.” Then comes the confusing part: adenomyosis and endometriosis can feel similar, can occur together, and can be hard to separate on imaging—yet your best treatment plan may depend on which one (or both) you have.

This post pulls together findings from multiple recent studies to answer the questions patients ask most: What’s the actual difference between endometriosis and adenomyosis? How often do they overlap? What signs point more to one vs the other? And why does it matter for fertility, symptom control, and choosing treatments?

Adenomyosis vs. endometriosis: the simplest explanation

Both conditions involve tissue that acts like the uterine lining (endometrium)—responding to hormones and contributing to inflammation and pain. The commonality is that they are both composed of cells that are molecularly "broken" in many ways. The key difference is location:

• Adenomyosis: endometrium-like tissue grows into the muscle wall of the uterus (the myometrium). It tends to be “within” the uterus.
• Endometriosis: endometrium-like tissue grows outside the uterus (for example on the ovaries, pelvic lining, or deeper tissues). It can involve multiple pelvic organs.

Because both can drive inflammation and pain, the lived experience can overlap. But adenomyosis is more likely to be tied to heavy/prolonged bleeding and a tender, enlarged uterus, while endometriosis is often associated with pain related to specific pelvic structures (for example deep pain with sex, bowel symptoms, or pain that’s not strictly proportional to bleeding).

How common are they—and how often do they occur together?

One reason patients get mixed messages is that prevalence depends heavily on who is being studied and how diagnosis is made. A 2025 systematic review and meta-analysis pooling global data found that in the general population, adenomyosis appeared around 1% and endometriosis around 5%—but those numbers rise sharply in people being evaluated for symptoms or infertility.

In studies of symptomatic women, pooled estimates for adenomyosis were strikingly high—roughly 40–50% across symptom groups like abnormal uterine bleeding, pelvic pain, dyspareunia, and dysmenorrhea. Endometriosis estimates in symptomatic groups varied more (roughly 18–42%, depending on the symptom subgroup). In infertility/subfertility populations, both were common in the included studies: about 31% for adenomyosis and 38% for endometriosis.

Two practical takeaways follow from this combined evidence:

1. If you’re being worked up for infertility or for persistent pelvic pain and/or heavy bleeding, it is reasonable to discuss both adenomyosis and endometriosis—not just one.
2. Headlines about prevalence can be misleading unless you know the diagnostic method. The meta-analysis showed big differences by how diagnoses were established (for example, endometriosis prevalence was far higher in studies using laparoscopy than in self-reported data). Also, pathology reported series show that adenomyosis can be present in up to 60% of uteri removed for various reasons.

Why the symptoms overlap so much

Adenomyosis and endometriosis share hormonal sensitivity and inflammatory signaling, which can translate into similar symptom patterns: cramping, chronic pelvic pain, pain with sex, bowel discomfort, fatigue, and reduced quality of life.

But overlap doesn’t mean identical. Clinically, the “feel” can differ:

• Adenomyosis often clusters with heavy bleeding, clots, an enlarged or “globular” uterus, and sometimes a uniquely tender uterus on exam.
• Endometriosis may show up as deep dyspareunia, pain that radiates or is positional, bowel/bladder pain around periods, or pain that persists even when bleeding is controlled.

In a real-world surgical cohort study (patients who ultimately had pathology from hysterectomy), uterine tenderness on bimanual exam stood out as the only independent clinical predictor associated with adenomyosis in multivariable analysis—more so than any single symptom pattern. That doesn’t mean tenderness “proves” adenomyosis, but it supports what many specialist clinicians emphasize: the pelvic exam can add meaningful information that symptoms and imaging alone may miss if the presence or absence of adenomyosis changes the surgical plan (e.g. fertility preservation vs not).

Diagnosis: why adenomyosis is often missed (and why endometriosis can be, too)

Ultrasound can help—but the way it’s interpreted matters

Transvaginal ultrasound (TVUS) is often the first-line test. The challenge is that adenomyosis signs can be subtle, inconsistently reported, or masked by other conditions.

A 2025 study looking at preoperative diagnosis found an alarming gap: routine radiology TVUS reports did not identify adenomyosis in patients who later had it confirmed on pathology, while a gynecology MIGS (minimally invasive gynecologic surgery) team re-reviewing the same ultrasounds detected it more often—especially when adenomyosis occurred without fibroids. Detection dropped substantially when fibroids coexisted, suggesting that fibroids can “hide” adenomyosis on imaging or shift attention away from it.

What that means as a patient: a report that focuses on fibroids (or says “normal”) doesn’t necessarily close the case if your symptoms fit. It may be worth asking whether your scan was assessed for adenomyosis features specifically—and whether a clinician experienced with adenomyosis imaging can review it.

Standardized ultrasound language may reduce confusion

A separate 2025 ultrasound study used the revised MUSA criteria (a standardized way to describe ultrasound features of adenomyosis) and found something particularly relevant to people who also have endometriosis: when adenomyosis occurred with endometriosis, it was more likely to show indirect ultrasound signs rather than “classic” direct signs.

In that study, myometrial cysts (a direct feature) were much more common in isolated adenomyosis than in adenomyosis with concurrent endometriosis. Meanwhile, the overall number of features per person didn’t differ much—suggesting it’s not just scans of “more severe cases,” but a different pattern.

Patient-friendly translation: if you have suspected/known endometriosis, an ultrasound that doesn’t show a dramatic “smoking gun” like myometrial cysts may still be consistent with adenomyosis—especially if indirect signs are present (for example a globular uterus or asymmetrical thickening). This is one reason standardized reporting can be helpful: it prompts the reader to consider the full pattern, not one single sign.

A note on endometriosis diagnosis

Endometriosis is still most commonly confirmed via laparoscopy, though imaging can identify certain forms reasonably well (like ovarian endometriomas or deep infiltrating disease). The prevalence meta-analysis underscores how strongly endometriosis rates shift depending on method—self-report produces much lower numbers than surgical confirmation—highlighting why some people are told they “don’t have endo” when the more accurate way to state that is “we haven’t proven you have endo.”

When both conditions are present: why it matters for care

The overlap isn’t just academic—it can change what you and your clinician prioritize.

• If adenomyosis is driving heavy bleeding and uterine tenderness, uterine-directed therapies (hormonal suppression, uterus-preserving procedures, or hysterectomy if finished with childbearing) may be central.
• If endometriosis is driving deep dyspareunia, bowel/bladder symptoms, or pain that persists despite controlling bleeding, evaluation for extra-uterine disease and targeted endometriosis management may be the main focus.

Coexistence can also complicate imaging interpretation (as the MUSA-pattern study suggests) and can affect which procedures you’re offered. For example, a 2026 pilot randomized trial of uterus-preserving procedures—ultrasound-guided microwave ablation (MWA) versus uterine artery embolization (UAE)—excluded people with suspected/verified endometriosis on imaging, as well as those with larger fibroids and those desiring pregnancy. That design makes the results cleaner, but it also highlights a real-world issue: if you have overlapping disease, you may not “fit” the evidence base for certain procedures.

Fertility: what the evidence suggests

Both conditions are common in infertility populations in the global meta-analysis, supporting that they matter in fertility workups. But “common” doesn’t automatically mean “the cause”—many people have one or both and still conceive.

Where the research gets practical is around treatment strategy in assisted reproduction. A 2025 randomized trial in symptomatic diffuse adenomyosis patients undergoing frozen embryo transfer compared 3 months of low-dose letrozole to 3 months of depot GnRH agonist pretreatment. The key result: IVF outcomes (clinical pregnancy, live birth, miscarriage) were similar between the two pretreatment approaches in that setting. Both treatments also shifted certain laboratory “implantation marker” profiles toward what the authors considered more receptive—though these markers are surrogate measures, and the clinical outcomes between the two medications weren’t meaningfully different.

One intriguing point from that trial: outcomes varied by lesion location, with junctional zone involvement associated with worse odds of pregnancy outcomes than outer myometrial involvement. For patients, this supports asking not only “Might I have adenomyosis?” but also “What type and where?”

Self-management and quality of life: what helps beyond medication and surgery?

Many people experiment with diet changes, exercise, yoga, mindfulness, and devices like TENS—often because symptoms are chronic and access to specialist care can be slow.

A 2026 scoping review mapped lifestyle interventions studied for pelvic pain in endometriosis or adenomyosis. Across varied (often small) studies, there were signals that some approaches—Mediterranean-style dietary counseling, certain structured exercise programs, yoga/mindfulness-based interventions, and electrotherapy/TENS—may improve pain or quality-of-life measures for some individuals. The big caveat: the evidence is heterogeneous and generally not strong enough to guarantee results.

A particularly important point for adenomyosis patients: adenomyosis-specific lifestyle evidence was sparse in that review (only one included trial explicitly included adenomyosis participants). So it’s reasonable to try low-risk options, but it’s also fair to hold expectations lightly and track your own response.

Sex and intimacy deserve special mention because pain conditions can reshape relationships and self-image. A 2026 randomized mixed-methods pilot study of a self-guided app program for endometriosis-related sexual distress found that people who used the app experienced improvements in sexual distress and sexual function at some time points, including follow-up—yet dropout was high, suggesting that purely self-guided tools can be emotionally demanding or hard to sustain without added support. Even among people who benefited, qualitative findings suggested that pain relief was not usually complete, but coping, communication, and avoidance patterns could improve.

Practical takeaways: how to advocate for the right evaluation

• Ask your clinician to talk in “either/or/both” terms: Could this be adenomyosis, endometriosis, or both? How would we tell?
• If your ultrasound report feels dismissive but symptoms persist, ask whether adenomyosis features were assessed systematically (for example with standardized criteria) and whether coexisting fibroids could be limiting visibility.
• If your exam shows a markedly tender uterus, mention it—research suggests this sign can meaningfully raise suspicion for adenomyosis in the right context.
• If fertility is a goal, ask about type and location of adenomyosis and how that might influence prognosis and pretreatment options before embryo transfer.
• If you’re considering uterus-preserving procedures (like UAE or ablation), ask how suspected endometriosis, fibroids, or pregnancy goals affect whether you’re a candidate—because many studies exclude those common real-world situations.

What we still don’t know (why your path may look different from someone else’s)

Despite better imaging and growing awareness, there are real evidence gaps:

• Diagnostic accuracy varies widely by setting and interpreter. Some cohorts show major under-recognition of adenomyosis on routine ultrasound reporting, and coexisting fibroids or endometriosis may change how adenomyosis appears.
• Many lifestyle and digital-health studies are small or pilot-level, and adenomyosis-specific data are limited—so recommendations often rely on endometriosis-heavy evidence.
• Even when treatments shift biological markers (as in the IVF pretreatment trial), the most important outcomes—pain relief, live birth, long-term recurrence—don’t always move in lockstep.
• Rare forms of endometriosis can mimic other conditions on imaging. Case-based literature describes unusual presentations (like polypoid endometriosis) that can look concerning preoperatively, underscoring why sometimes tissue diagnosis is necessary to clarify what’s going on.

Bottom line: adenomyosis vs. endometriosis isn’t a simple fork in the road. They can coexist, blur together symptom-wise, and require a layered diagnostic approach. The goal isn’t to “win” the perfect label—it’s to identify what’s most likely driving your symptoms and choose treatments that match your goals (pain control, bleeding control, fertility, and quality of life).