Adenomyosis and endometriosis are two related but different conditions that both involve the presence of endometrial-like tissue where it doesn’t belong. But they affect the body in different ways—and require different treatment approaches.
In adenomyosis, the endometrial tissue grows into the muscular wall of the uterus. This can cause the uterus to enlarge and often leads to heavy, painful periods. The condition is confined to the uterus.
Endometriosis, on the other hand, occurs when similar tissue grows outside the uterus—most commonly on the ovaries, fallopian tubes, and other pelvic organs. Because endometriosis can affect other organs, it can cause a broader range of symptoms, including painful sex, digestive issues, and infertility.
While adenomyosis and endometriosis share symptoms like pelvic pain and heavy bleeding, their underlying causes and patterns of progression are different. That’s why an accurate diagnosis—often through imaging, surgical evaluation, or both—is essential.
Adenomyosis and Endometriosis 101
Adenomyosis and endometriosis are two separate conditions that can both cause pelvic pain and heavy periods. While they share some symptoms, the key difference lies in where the endometrial-like tissue grows and how it affects the body.
How Adenomyosis Works
In adenomyosis, endometrial tissue grows into the muscular wall of the uterus (the myometrium). This can lead to an enlarged, tender uterus and often results in painful, heavy menstrual bleeding. The condition is limited to the uterus but can significantly affect comfort and quality of life.
How Endometriosis Works
Endometriosis occurs when endometrial-like tissue grows outside the uterus. It commonly affects the ovaries, fallopian tubes, bladder, and other abdominal organs. This tissue responds to hormonal changes, just like normal endometrial lining, which can cause chronic inflammation, scar tissue, and adhesions. In more advanced cases, endometriosis may also affect organs outside the pelvis.
What They Have in Common
Both endometriosis and adenomyosis are estrogen-sensitive, meaning symptoms often worsen during the reproductive years (particularly during menstruation) and may ease after menopause. They also share symptoms such as pelvic pain, painful periods, and heavy bleeding. Because of this overlap, diagnosis can be challenging and may require imaging or surgical evaluation.
Key Differences: Location and Impact
The main distinction is location.
Adenomyosis involves tissue growing within the uterine muscle, while endometriosis involves tissue growing outside the uterus. This difference affects not only symptoms but also how each condition is diagnosed and treated.
Adenomyosis and Endometriosis Symptoms
Adenomyosis and endometriosis share some common symptoms, which can make it difficult to tell them apart without further evaluation. Both conditions may involve:
- Pelvic pain or cramping
- Heavy or prolonged menstrual bleeding
- Painful periods (dysmenorrhea)
- Pain during sex (dyspareunia)
Despite these similarities, each condition also has symptoms that are more specific.
Symptoms More Common in Adenomyosis
Adenomyosis affects the uterus directly and may cause:
- An enlarged, tender, or "boggy" uterus (detectable by a clinician during a pelvic exam)
- A feeling of pressure or heaviness in the pelvic area
- Menstrual cramps that worsen with age
- Heavy, painful periods
Symptoms More Common in Endometriosis
Endometriosis often involves tissues outside the uterus and may lead to:
- Constant pelvic pain that occurs even outside of periods
- Pain during bowel movements or urination, especially during menstruation
- Gastrointestinal symptoms like bloating, diarrhea, or constipation during menstrual periods
- Difficulty getting pregnant (infertility)
Causes and Risk Factors
The exact causes of adenomyosis and endometriosis still aren’t fully understood, but researchers have identified several possible mechanisms and risk factors for each condition.
Possible Causes
Adenomyosis:
Theories about what causes adenomyosis include:
- Direct invasion: Endometrial tissue may grow directly into the uterine muscle (myometrium)
- Developmental factors: The condition may originate during fetal development
- Stem cell involvement: Bone marrow stem cells might contribute to abnormal tissue growth
- Hormonal influences: Estrogen and progesterone imbalances may play a role in how endometrial tissue behaves
Endometriosis:
There are also several theories that try to explain how endometrial-like tissue ends up outside the uterus:
- Retrograde menstruation: Menstrual blood flows backward through the fallopian tubes into the pelvic cavity
- Cell transformation: Cells outside the uterus may change into endometrial-like cells (metaplasia)
- Embryonic remnants: Cells left from embryo development may later develop into endometrial-like tissue
- Surgical spread: Endometrial cells may implant on tissues during pelvic surgeries
- Vascular or lymphatic spread: Cells may travel through the bloodstream or lymphatic system
Risk Factors
Adenomyosis:
You're more likely to develop adenomyosis if you:
- Are between 40 and 50 years old
- Have had children
- Have had uterine surgery, such as a C-section or fibroid removal
- Have used tamoxifen, a drug used in breast cancer treatment (and sometimes in prevention)
Endometriosis:
Risk factors for endometriosis include:
- Family history, especially having a first-degree relative (mother or sister) with the condition
- Starting menstruation early (before age 11 or 12)
- Short menstrual cycles (less than 27 days)
- Heavy or prolonged periods
- Delayed childbearing or never giving birth
- Having a low body mass index (BMI)
- Regular alcohol use
- Certain immune system disorders
Adenomyosis vs. Endometriosis Diagnosis
Diagnosing adenomyosis and endometriosis can be difficult. Dr. Jessica Opoku-Anane explains that the two conditions often share many similar symptoms, such as pelvic pain, heavy bleeding, and pain during sex, and can occur at the same time.
These similarities make it hard to tell them apart based on symptoms alone.
Imaging tests, like ultrasounds or MRIs, may help identify the features of adenomyosis or suggest the presence of endometriosis. But in many cases, the results aren’t definitive. The features of these conditions can overlap on imaging, and sometimes, abnormalities may not show up at all. This is one reason it’s important to work with a provider who has specific experience diagnosing and managing these conditions.
In some cases, a laparoscopic surgery may be the only way to definitively diagnose endometriosis. During this minimally invasive procedure, a medical provider uses a small camera to look inside the pelvis. If endometriosis is present, they can take a biopsy or remove visible lesions during the same procedure. This makes laparoscopy both a great diagnostic tool and a potential first step in treatment.
Treatment Options
Treatment for adenomyosis and endometriosis will depend on a few different factors, including your age, symptoms, and whether you’re planning to get pregnant.
Common treatment approaches include medication, hormonal therapy, and—in some cases—surgery. Each option has its benefits and trade-offs, and the right choice will depend on your individual situation.
Medications and Pain Management
Managing pain is often the first priority. Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen or naproxen, are often used to relieve menstrual cramps and pelvic pain. If symptoms are more severe, a provider may recommend:
- Prescription-strength NSAIDs
- Short-term use of opioids
- Antidepressants or anticonvulsants (used off-label for chronic pelvic pain)
These medications don’t treat the underlying condition but can help regulate how the nervous system processes persistent pain, especially if pain is ongoing and not tied to the menstrual cycle alone.
Hormonal Therapies
Hormonal treatments aim to lower your estrogen levels or block its effects. This can slow the growth of endometrial tissue and help reduce symptoms like pain and heavy bleeding.
Treatment options include:
- Combined hormonal contraceptives (pill, patch, or vaginal ring) to regulate menstrual cycles and reduce bleeding and pain
- Progestin-only options, such as:
- The mini-pill
- The injection (Depo-Provera)
- Hormonal implant
- Levonorgestrel-releasing IUDs (e.g., Mirena), which deliver progestin directly into the uterus, are often used for adenomyosis and sometimes helpful for endometriosis
- GnRH agonists or antagonists to temporarily reduce estrogen and relieve symptoms; typically only used short-term due to potential side effects like:
- Hot flashes
- Vaginal dryness
- Bone loss
Surgical Approaches
When other treatments aren’t effective, surgery could be a consideration.
For adenomyosis:
- A hysterectomy (removal of the uterus) is the only definitive treatment.
- This may be recommended if you don’t want to get pregnant in the future and symptoms haven’t responded to medication or hormonal therapy.
For endometriosis:
- Laparoscopic surgery is the most common surgical approach. It allows your provider to locate and remove endometriosis lesions and scar tissue through small incisions.
- In more severe or persistent cases, hysterectomy with or without removal of the ovaries may be discussed, but this is not always necessary and should be weighed carefully.
Impact on Fertility and Pregnancy
Adenomyosis and endometriosis can both make it more difficult to conceive, though the reasons differ slightly between the two conditions.
In adenomyosis, the structure and function of the uterus may be altered. This can make it harder for an embryo to implant and grow.
In endometriosis, fertility can be affected by damage to the fallopian tubes or ovaries, or by chronic inflammation in the pelvic area, which may interfere with ovulation, fertilization, or implantation.
Not everyone with adenomyosis or endometriosis will struggle to conceive, but if pregnancy doesn’t occur after a period of trying (12 months if you’re under 35, 6 months if you’re 35 or older), a fertility evaluation may be recommended. In some cases, assisted reproductive technologies—such as in vitro fertilization (IVF)—can improve your chances of conception.
Pregnancy can also temporarily suppress symptoms of adenomyosis and endometriosis due to the rise in progesterone. This hormonal shift can suppress endometrial tissue growth and reduce inflammation. However, symptom relief is usually temporary, and symptoms often return after delivery.
Choosing the Right Care
Adenomyosis and endometriosis are both complex conditions, and effective care often depends on getting an accurate diagnosis and working with the right specialists. Treatment plans should be tailored to your specific symptoms, reproductive goals, and overall health.
For reliable information, Roon’s Basics of Endometriosis is a good starting point. If you have specific questions, our Q&A platform offers information from medical specialists like gynecologic surgeons and reproductive endocrinologists, whose insights can help guide decisions about diagnosis, treatment, and long-term management.
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Frequently Asked Questions (FAQ):
Which is more serious – endometriosis or adenomyosis?
Both conditions can significantly affect quality of life, but they present differently and impact the body in distinct ways. Endometriosis is often more associated with infertility and chronic pelvic pain, while adenomyosis tends to cause heavy menstrual bleeding and cramping.
What are the 4 stages of adenomyosis?
Unlike endometriosis, adenomyosis doesn’t have an official staging system. However, it can vary in severity based on how deeply the endometrial tissue grows into the uterine muscle and how much of the uterus is affected.
What happens if adenomyosis is left untreated?
Without treatment, adenomyosis can lead to ongoing or worsening symptoms, including heavy or prolonged menstrual bleeding, severe cramps and pelvic pain, fatigue, anemia (due to blood loss), and possible impact on fertility.
Can I get pregnant with adenomyosis?
Yes, pregnancy is still possible with adenomyosis, though it may take longer to conceive. Adenomyosis can interfere with implantation or early pregnancy in some people, but others have no fertility issues.
Should I get a hysterectomy if I have adenomyosis?
A hysterectomy is considered the definitive treatment for adenomyosis because it removes the uterus entirely. It may be recommended if your symptoms are severe and haven't responded to other treatments, or if you don’t plan to become pregnant in the future and are looking for long-term relief.
