Adenomyosis is not a rare condition. It is not a minor inconvenience. And it is not, as women are too often told, simply “bad periods.” It is a chronic, progressive gynaecological disorder that affects a significant proportion of reproductive-aged women, causes measurable damage to fertility and quality of life, and carries an average diagnostic delay of eleven years.

Eleven years of pain, misdiagnosis, and unanswered questions, before a name is finally given to what a woman has been experiencing.

This article presents what the current evidence shows: what adenomyosis is, how it is diagnosed, how it is treated, and why earlier, more accurate clinical recognition matters.

What Adenomyosis Is

Uterine adenomyosis is defined by the presence of endometrial glands and stroma, tissue that normally lines the uterine cavity, within the myometrium, the muscular wall of the uterus. This ectopic tissue responds to cyclic hormonal signals just as normal endometrium does: it proliferates, swells, and bleeds. But because it is trapped within muscle, there is nowhere for that blood to go. The result is progressive inflammation, hypertrophy of the surrounding smooth muscle, and a uterus that becomes enlarged, boggy, and chronically painful.

The condition was first described in 1860 by the German pathologist Carl von Rokitansky. It was historically referred to as “endometriosis interna”, a term now formally abandoned, as the 2022 European Society of Human Reproduction and Embryology (ESHRE) guidelines confirmed that adenomyosis is a distinct clinical entity with its own pathogenesis, requiring a dedicated and separate diagnostic and therapeutic approach.

How It Develops: The Biology

The precise biological mechanisms driving adenomyosis remain an area of active scientific inquiry. Two primary theories currently dominate the literature.

The most widely accepted is the invagination theory, closely aligned with the Tissue Injury and Repair (TIAR) hypothesis. This framework proposes that physiological or iatrogenic microtrauma to the junctional zone, the border between the endometrium and myometrium, resulting from pregnancy, childbirth, caesarean sections, dilation and curettage, or myomectomy, disrupts the endometrial-myometrial interface. 

The subsequent wound-healing response creates a localized, hyperestrogenic and inflammatory microenvironment characterized by progesterone resistance, increased cyclooxygenase-2 (COX-2) activity, and prostaglandin hyperproduction. 

These molecular alterations trigger epithelial-mesenchymal transition and collective cell migration, prompting basal endometrial cells to acquire an invasive phenotype and migrate into the injured myometrium.

An alternative, embryologically grounded theory proposes that adenomyosis arises from the inappropriate differentiation of pluripotent Müllerian stem cells, displaced embryonic remnants that persist within the myometrial wall and undergo reactivation under cyclic ovarian hormonal influence during adult life.

Recent molecular and genomic studies have added further nuance to these models. Evidence from Frontiers in Genetics (2025) demonstrates that local hyperestrogenism upregulates the palmitoylation enzymes APT1 and APT2, which promote depalmitoylation of the Scribble polarity protein. This causes Scribble to translocate from the cell membrane to the cytoplasm, disrupting the polarity of endometrial epithelial cells, dramatically enhancing their proliferative, migratory, and invasive capacity. This molecular pathway also represents a highly specific target for future non-hormonal therapeutics.

Both estrogen and progesterone contribute directly to disease progression. Estrogen appears to function as a mitogen for adenomyotic tissue, while progesterone resistance, a hallmark of the disease, impairs the normal anti-proliferative response that would otherwise limit tissue growth.

How Common It Is

Determining the true prevalence of adenomyosis has historically been difficult, because diagnosis traditionally required post-hysterectomy histopathological confirmation. The introduction of high-resolution transvaginal ultrasound and MRI has significantly revised our understanding of the disease’s reach.

A systematic review and meta-analysis published in 2025, synthesising data from 127 studies representing 198,925,726 women, reported the following pooled prevalence estimates across clinical populations:

In the general population, adenomyosis affects approximately 1% of women. Among symptomatic gynaecological cohorts, however, prevalence rises to between 41% and 49%. Among infertile women, adenomyosis is identified in approximately 31% of cases, with confidence intervals ranging from 10% to 58% depending on the diagnostic method used. Focal adenomyosis accounts for approximately 17% of cases, while diffuse adenomyosis is identified in approximately 15%.

While the condition was historically described as a disease of multiparous, perimenopausal women in their thirties and forties, it is increasingly diagnosed in younger, nulliparous patients presenting with abnormal uterine bleeding, dysmenorrhoea, or subfertility. Studies utilising imaging-based diagnosis report prevalence rates of 20% to 35% in younger populations, with one study reporting a mean age of 26 years at diagnosis.

Key epidemiological risk factors include early menarche, short menstrual cycles, elevated body mass index, multiparity, and a history of uterine surgery. These factors are united by their association with either increased estrogen exposure or disruption of the endometrial-myometrial interface.

What It Feels Like: Symptoms and Their Mechanisms

Approximately two-thirds of women with adenomyosis present with highly disruptive clinical symptoms. The remaining third may be asymptomatic, though more recent studies report asymptomatic rates as low as 4.5%, suggesting that the historical estimate of one-third was a significant overestimate.

Heavy menstrual bleeding, defined as abnormal uterine bleeding in the FIGO PALM-COEIN classification, occurs in 40% to 60% of patients. It is driven by the expanded endometrial surface area of an enlarged uterus, increased vascularisation within the myometrium, and atypical uterine contractions caused by structural disruption of the smooth muscle. Chronic blood loss of this magnitude frequently produces iron-deficiency anaemia, with patients suffering severe fatigue, dizziness, and cognitive exhaustion that significantly impair daily functioning.

Dysmenorrhoea, severe menstrual cramping, is reported by 15% to 30% of patients in general population studies, though rates reach 25% to 80% in symptomatic clinical cohorts. Pain arises from intramyometrial bleeding from ectopic glands, combined with hyperproduction of inflammatory mediators including prostaglandins and eicosanoids. Chronic pelvic pain, present outside of menstruation, affects up to 77% of symptomatic women.

Less common but clinically significant symptoms include deep dyspareunia, reported by approximately 7% of patients, a persistent dragging or bearing-down sensation in the pelvis and thighs, and localized bladder or bowel pressure from uterine enlargement. The combination and variability of these symptoms contributes substantially to the high rates of misdiagnosis and diagnostic delay that characterise this disease.

The Diagnostic Delay: Eleven Years

One of the most consequential, and preventable, features of adenomyosis is the duration between symptom onset and diagnosis. Recent large-scale clinical data reveals that women face an average diagnostic delay of eleven years for adenomyosis and ten years for endometriosis from the onset of their first symptoms.

This delay is driven by a combination of clinical, societal, and socioeconomic factors. Studies show that up to 75.2% of patients with pelvic pain are initially misdiagnosed with other physical or mental health conditions, with gynaecologists and general practitioners being the most common sources of initial misdiagnosis. Society’s persistent tendency to normalise severe menstrual pain as “just bad cramps” causes women to delay seeking care, while the presentation of multiple non-specific symptoms leads clinicians toward alternative diagnoses.

Factors independently associated with longer diagnostic delays include unemployment, a higher number of comorbidities, a family history of chronic pelvic pain, high pre-diagnosis pain severity, and consulting multiple healthcare providers. Conversely, a perceived comfortable financial position is associated with a 1.4-year shorter diagnostic delay, a finding that highlights significant socioeconomic disparities in access to timely, specialised gynaecological care.

The Psychological Burden

The toll of living with adenomyosis extends well beyond physical pain. Patients with adenomyosis exhibit a markedly higher prevalence of clinically significant mental health difficulties compared to healthy populations. Anxiety is diagnosed in 16% of affected women, compared to 2% of controls. Depression is observed in 20% of affected women, compared to 2% of controls. Some clinical studies report depression rates reaching 57.1% among adenomyosis patients, with a significantly higher requirement for antidepressant therapy compared to women with uterine fibroids.

Chronic pain alters neural pain-processing pathways, making emotional regulation difficult and contributing to social withdrawal, mood dysregulation, sleep disturbance, and compounded daytime fatigue. The unpredictability of symptom flare-ups creates persistent anticipatory anxiety, forcing women to cancel plans, miss work, and withdraw from activities. In the workplace, chronic pain and heavy bleeding produce significant absenteeism and presenteeism, including cognitive changes such as memory lapses, difficulty focusing, and slowed processing during severe pain episodes.

Severe dyspareunia and unpredictable bleeding frequently produce anxiety around sexual intimacy, leading to avoidance, partner strain, and a profound sense of body betrayal. For women experiencing fertility challenges secondary to the disease, the emotional impact is further compounded by grief, guilt, and a loss of identity that requires dedicated, multidisciplinary psychological support.

How It Is Diagnosed

A definitive diagnosis of adenomyosis has historically required post-hysterectomy histopathological analysis, identifying endometrial tissue within the myometrium at least 2.5 to 8 mm below the endometrial-myometrial junction. Today, high-resolution transvaginal ultrasound and pelvic MRI allow for accurate presumptive diagnosis without surgical intervention.

Transvaginal ultrasound (TVUS) is established as the primary, first-line imaging modality. In the hands of trained specialists, TVUS achieves a diagnostic accuracy of approximately 89%. The Morphological Uterus Sonographic Assessment (MUSA) group developed standardised sonographic criteria, revised to distinguish between direct features (indicating the physical presence of ectopic tissue within the myometrium) and indirect features (indicating secondary structural and vascular changes). Direct features include myometrial cysts of 1 to 5 mm, hyperechogenic islands, and echogenic subendometrial lines or buds. Indirect features include a globular uterus, identified as the overall most statistically predictive single feature, an irregular or interrupted junctional zone, asymmetric myometrial thickening, fan-shaped shadowing, and translesional vascularity on colour Doppler. Clinical validation studies demonstrate that the presence of more than four sonographic features serves as a highly predictive, statistically validated diagnostic threshold for adenomyosis using the revised MUSA criteria (p < 0.001).

Pelvic MRI functions as a highly specific second-line diagnostic tool, particularly when TVUS findings are inconclusive, when concurrent uterine fibroids are present, or when planning conservative, uterus-sparing surgery. The primary MRI criterion for adenomyosis is a junctional zone thickness of at least 12 mm, while a thickness below 8 mm makes the diagnosis unlikely. Additional validated criteria include a junctional zone-to-myometrium ratio exceeding 40%, a junctional zone thickness variability of more than 5 mm between the thinnest and thickest regions, and the identification of high-intensity myometrial cysts on T2-weighted sequences. MRI diagnostic sensitivity and TVUS sensitivity are comparable at 78% to 79%, but MRI specificity is higher at 93% versus 80% for TVUS, meaning MRI produces significantly fewer false positive diagnoses.

There are no laboratory tests that diagnose adenomyosis. Serum CA-125 has been validated as a useful adjunct marker, with clinical cutoffs of 35 U/mL or 44.8 U/mL correlating positively with dysmenorrhoea severity, disease subtype, and lesion volume, but its diagnostic specificity remains limited, as CA-125 is also elevated in endometriosis, uterine fibroids, and pelvic malignancies.

Adenomyosis and Endometriosis: Related but Distinct

Adenomyosis and endometriosis are both chronic, estrogen-dependent inflammatory disorders characterised by the ectopic presence of endometrial-like tissue. Their clinical similarities historically led to adenomyosis being categorised as a subtype of endometriosis, hence the outdated term “endometriosis interna.” The 2022 ESHRE guidelines formally reaffirmed that they are distinct clinical entities with different pathogeneses, anatomical distributions, and diagnostic approaches.

The key anatomical distinction is location: adenomyosis involves tissue within the uterine myometrium, while endometriosis involves tissue outside the uterus, on the ovaries, fallopian tubes, peritoneum, and adjacent organs. Their symptom profiles overlap substantially, but adenomyosis more characteristically presents with severe heavy menstrual bleeding and uterine enlargement, while endometriosis more characteristically presents with deep dyspareunia and infertility in the context of normal or near-normal uterine volume.

The clinical coexistence of these two conditions is remarkably high. Studies report that between 15% and 90% of women diagnosed with endometriosis also have concurrent adenomyosis, depending on the diagnostic methods used. When both conditions coexist, they create a synergistic inflammatory environment that severely exacerbates chronic pelvic pain, dysmenorrhoea, and deep dyspareunia, while significantly complicating clinical management and reducing the success rates of conservative therapies. In patients with persistent pelvic pain following optimal surgical treatment for endometriosis, the presence of concurrent adenomyosis should be actively considered.

Emerging genomic research suggests a partially shared origin: somatic mutations within endometrial epithelial cells may prompt some cells to implant ectopically on peritoneal surfaces, producing endometriosis, while others become entrapped within the myometrium, producing adenomyosis.

Impact on Fertility

The relationship between adenomyosis and subfertility is well established. The disease creates a hostile uterine environment characterised by myometrial hyperperistalsis, chronic local inflammation, local hyperestrogenism, immune cell activation, and severe progesterone resistance, all of which systematically impair endometrial receptivity and compromise trophoblastic invasion.

A meta-analysis published in Human Reproduction (Oxford Academic) evaluating 11 cohort studies including 2,054 patients undergoing IVF found that women with adenomyosis had significantly lower rates of implantation, clinical pregnancy per cycle, clinical pregnancy per embryo transfer, ongoing pregnancy, and live birth compared to women without adenomyosis.

A 2024 systematic review and meta-analysis presented at the European Society of Human Reproduction and Embryology congress quantified these effects. Compared to women without adenomyosis, affected women showed a significant reduction in implantation rate, a 28% reduction in clinical pregnancy rate, a reduced live birth rate, and a doubled overall miscarriage risk. Placenta previa, pre-eclampsia, small-for-gestational-age infants, and caesarean delivery rates were all significantly elevated.

Critically, these negative reproductive effects persist even in donor oocyte cycles and euploid embryo transfers. This is a decisive finding: it demonstrates that the subfertility associated with adenomyosis is not primarily an oocyte-quality issue, but rather a profound, localised uterine and endometrial failure to support implantation and early placentation. The uterus itself is the limiting factor.

Current clinical guidelines recommend pre-treatment with GnRH agonists prior to both fresh and frozen embryo transfers in women with adenomyosis-associated subfertility undergoing IVF, with the aim of downregulating the inflammatory uterine microenvironment and temporarily regressing lesions to enhance implantation rates. Pregnant patients with adenomyosis must be managed as high-risk obstetric cases, with close antenatal monitoring for pre-eclampsia, placenta previa, and fetal growth restriction.

Medical Treatment

Medical management is the first-line therapeutic approach for symptomatic women who wish to avoid surgery or preserve fertility. Because no universal, standardised clinical guideline specifically for adenomyosis currently exists, clinicians frequently utilize hormonal therapies, largely off-label, to induce a hypoestrogenic state, suppress menstrual cycles, and promote regression of ectopic tissue.

The levonorgestrel-releasing intrauterine system (LNG-IUS), releasing 20 micrograms of levonorgestrel per day directly into the uterine cavity, is widely regarded as one of the most effective and well-evaluated long-term treatments for both heavy menstrual bleeding and adenomyosis-associated pelvic pain. The local release of progestin drives extensive stromal decidualization, endometrial gland atrophy, and downregulation of estrogen receptors, resulting in significant pain reduction, decreased uterine volume, and high levels of patient satisfaction. Studies indicate that the LNG-IUS is comparable to hysterectomy in improving haemoglobin levels and patient quality of life. It is the preferred first-line option for patients seeking long-term symptom control without immediate fertility goals.

Oral progestin dienogest is highly effective for adenomyosis-associated pelvic pain. A systematic review and network meta-analysis of randomised controlled trials published in Frontiers in Endocrinology (2025) found that dienogest achieved a rapid and pronounced reduction in pain scores, superior to placebo, combined oral contraceptives, and the LNG-IUS at the three-month mark. At six months, dienogest continued to demonstrate superior pelvic pain reduction compared to combined oral contraceptives. However, dienogest carries a higher risk of systemic adverse events, including irregular breakthrough bleeding and mood alterations, leading up to 49% of patients to switch therapies after one year of continuous use.

Combined oral contraceptives can suppress dysmenorrhoea and induce temporary lesion regression but perform significantly worse than other options in reducing the number of bleeding days.

GnRH agonists, such as leuprolide acetate, induce a profound but reversible medical menopause by downregulating pituitary receptors. They are highly effective at reducing both pelvic pain and uterine volume, but their use is clinically restricted to short-term courses of three to six months due to severe vasomotor symptoms and the risk of bone mineral density loss. They are primarily used as a preoperative bridge to surgery or as pre-treatment prior to embryo transfer in assisted reproduction.

Oral GnRH antagonists represent a significant therapeutic advancement. Unlike GnRH agonists, they achieve rapid, dose-dependent estrogen suppression without an initial hormonal flare. Relugolix, administered as a once-daily combination tablet with estradiol and norethindrone acetate as add-back therapy, demonstrated exceptional efficacy in the LIBERTY trials. In women with concurrent fibroids and adenomyosis, relugolix combination therapy achieved an 83.8% bleeding response rate compared to 27.6% for placebo, induced amenorrhoea in 64.9% of patients, and reduced mean uterine volume by 22.2%. Linzagolix has been evaluated in a novel “hit hard first, then maintain” regimen, 200 mg daily for 12 weeks followed by 100 mg daily, achieving a 55% reduction in uterine volume at 12 weeks and a 32% reduction at 24 weeks, while significantly minimising bone mineral density loss and vasomotor side effects.

When hormonal medications are discontinued, for example, when a patient wishes to conceive, recurrence of symptoms and uterine enlargement typically occur within six months.

For patients actively trying to conceive, hormonal suppressants are contraindicated. NSAIDs remain the primary medical option in this context, reducing acute pain and menstrual blood loss by decreasing circulating uterine prostaglandins, though they are less effective than hormonal agents.

Surgical and Interventional Treatment

Hysterectomy remains the definitive, curative treatment for patients who have completed childbearing and in whom medical management has failed. It is the only intervention that eliminates the disease entirely, with zero risk of recurrence. Minimally invasive laparoscopic or vaginal approaches are preferred over laparotomy due to faster recovery and reduced postoperative morbidity. Subtotal hysterectomy must be avoided, as ectopic tissue can persist and recur within the cervical stump or rectovaginal septum.

Uterine artery embolization (UAE) offers an alternative for patients who decline or have contraindications to hysterectomy. Studies report a 25% reduction in uterine volume and clinical improvement in abnormal bleeding and overall symptom burden. A meta-analysis of observational studies reported recurrence and reintervention rates of 29.5% and 12.8% respectively over follow-up periods of six months to seven years. UAE is not recommended for patients who wish to optimise future fertility, as it significantly compromises myometrial integrity and endometrial perfusion.

Conservative uterus-sparing surgery (adenomyomectomy) may be considered for patients with focal adenomyosis who desire future childbearing and in whom first-line therapies have failed. Unlike uterine fibroids, which can be readily excised from surrounding myometrium, adenomyotic lesions are highly infiltrative and lack clear surgical margins. Complete excision cannot be guaranteed. The reported rate of uterine rupture in subsequent pregnancies following uterus-sparing resection is approximately 4%, exceeding the rupture rate after myomectomy or classical caesarean section. Patients must be thoroughly counselled regarding this risk, and elective pre-labour caesarean delivery is mandatory in all subsequent pregnancies. A meta-analysis of 12 studies reported that of 364 patients who attempted to conceive following uterus-sparing surgery, 35% were successful, with 74% delivering at full term.

High-Intensity Focused Ultrasound (HIFU) and radiofrequency thermal ablation represent emerging minimally invasive options showing promise for symptom improvement and uterine volume reduction in selected patients, with recurrence and reintervention rates of approximately 10% at one to five years of follow-up.

A Note From the Clinic

At Nexxmedis, we offer comprehensive gynaecological evaluation for women with suspected adenomyosis, including transvaginal ultrasound with MUSA criteria assessment and, where indicated, referral for pelvic MRI. We work with patients across all stages of the condition: from initial diagnosis and medical management to fertility planning and surgical consultation.

If you have been experiencing heavy, painful periods that affect your daily life, if you have received a diagnosis elsewhere without a clear management plan, or if you are facing fertility challenges and suspect adenomyosis may be a contributing factor, a consultation with Dr. Diana Dram-Flutur will give you a clear picture and a concrete next step.

This article is based on current peer-reviewed evidence and international clinical guidelines as of June 2026. It is intended for informational purposes and does not constitute medical advice. All clinical decisions should be made in consultation with a qualified healthcare professional.

Sources & References

• UpToDate: Uterine Adenomyosis, Diagnosis and Management (2026)
• Frontiers in Endocrinology: Efficacy and safety of hormone therapies for adenomyosis-associated pelvic pain (2025)
• Human Reproduction, Oxford Academic: Uterine adenomyosis and IVF outcomes, systematic review (2024)
• European Society of Human Reproduction and Embryology: Endometriosis and Adenomyosis (2022)
• Frontiers in Genetics: Novel biomarkers related to palmitoylation in adenomyosis (2025)