Adenomyosis and uterine fibroids are two different conditions that can cause pelvic pain, painful periods, and heavy menstrual bleeding. Adenomyosis occurs when tissue from the uterine lining grows into the muscle wall, while fibroids are noncancerous growths made of uterine muscle. Both can cause discomfort, but the pattern of pain, other symptoms, and findings on imaging can help healthcare professionals distinguish between them.
How are adenomyosis and fibroids different?
The main difference is where and how the abnormal tissue develops. In adenomyosis, tissue similar to the uterine lining grows within the muscular wall of the uterus. In fibroids, muscle cells form distinct growths in or around the uterus. Both conditions can affect the uterus's size and function, but they do not cause exactly the same symptoms in everyone.
According to the NHS guide to adenomyosis, adenomyosis can cause painful periods, heavy bleeding, and pelvic discomfort. The NHS guide to fibroids explains that fibroids may also cause heavy bleeding and pain, as well as pressure on nearby organs. Some people have either condition without noticeable symptoms.
Key differences at a glance
| Feature | Adenomyosis | Uterine fibroids |
|---|---|---|
| What it is | Uterine-lining-like tissue within the muscle wall | Noncancerous growths made of uterine muscle |
| Typical pain pattern | Often painful menstrual cramps and pelvic aching | May cause pressure, aching, cramps, or pain related to the size and location of the growths |
| Menstrual bleeding | Periods may be heavy or painful | Periods may be heavy, prolonged, or otherwise disruptive |
| Abdominal or pelvic fullness | May occur if the uterus becomes enlarged | May occur when fibroids enlarge the uterus or press on nearby structures |
| How it is investigated | Medical history, examination, ultrasound, and sometimes MRI | Medical history, examination, ultrasound, and sometimes MRI or other imaging tests |
These differences describe common patterns, not a reliable way to identify either condition from symptoms alone. The two conditions can occur together, and other causes of pelvic pain may need to be considered.
What does pelvic pain from adenomyosis feel like?
Adenomyosis is often associated with painful menstrual cramps that may become more troublesome over time. Pain can occur in the lower abdomen or pelvis and may be accompanied by heavy periods or a feeling of fullness. Some people also experience pain during sex or pelvic discomfort outside their menstrual period.
The pain may be linked to the menstrual cycle, but its timing and intensity can differ from person to person. Some people with adenomyosis have no symptoms at all. The condition may also cause the uterus to become enlarged or tender, which a healthcare professional may notice during an examination.
- Menstrual cramps that interfere with daily activities.
- Heavy or prolonged menstrual bleeding.
- Aching or pressure in the lower abdomen.
- Pain during sexual intercourse.
- A sensation of abdominal heaviness or fullness.
These are possible experiences associated with adenomyosis, not symptoms that prove the condition is present. For further details on symptoms and assessment, see MedlinePlus: Adenomyosis.
How do fibroids cause pelvic pain and pressure?
Fibroids vary in number, size, and location. Some remain small and cause no symptoms, while others may contribute to menstrual cramps, pelvic discomfort, or a feeling of pressure. The location of a fibroid can be just as important as its size: growths that affect the uterine cavity may be associated with heavy bleeding, while larger growths can press against nearby organs.
Unlike the often cycle-related pain associated with adenomyosis, fibroid-related discomfort may include a more persistent feeling of pelvic heaviness or pressure. Depending on their size and position, fibroids may also contribute to urinary frequency or difficulty passing stools. However, pressure symptoms are not exclusive to fibroids and can have other causes.
- Heavy or prolonged menstrual periods.
- Menstrual cramps or aching in the pelvis.
- A sense of fullness, heaviness, or swelling in the lower abdomen.
- Frequent urination or difficulty emptying the bladder when nearby structures are affected.
- Constipation or discomfort with bowel movements in some cases.
According to Mayo Clinic's information on fibroid diagnosis and treatment, the symptoms and management options depend on factors such as the fibroids' size, number, and location. Pelvic pain alone cannot establish that fibroids are responsible.
Can adenomyosis and fibroids occur together?
Yes. A person can have both adenomyosis and uterine fibroids. When this happens, it may be difficult to determine which condition contributes most to pelvic pain or heavy menstrual bleeding. Symptoms may overlap, and finding fibroids on a scan does not automatically mean they explain every symptom.
A healthcare professional may consider the location of any fibroids, the appearance of the uterine muscle, the pattern of menstrual symptoms, and whether other pelvic conditions could be contributing. The aim is to understand which findings are most likely to explain the person's symptoms before deciding whether treatment is needed.
How do doctors tell adenomyosis and fibroids apart?
Assessment usually begins with questions about the pain and menstrual history. A clinician may ask when the pain occurs, whether it is getting worse, how heavy the bleeding is, whether there is pain during sex, and whether urinary or bowel symptoms are present. A physical or pelvic examination may help identify uterine enlargement, tenderness, or an irregular shape.
Ultrasound and MRI
Pelvic ultrasound is commonly used to examine the uterus and look for fibroids or features that may suggest adenomyosis. A transvaginal ultrasound uses a probe placed in the vagina to provide detailed images, while a transabdominal ultrasound examines the pelvis through the abdomen. The appropriate approach depends on the clinical situation and the person's circumstances.
MRI may be recommended when ultrasound findings are unclear or more detailed information is needed. It can help clinicians assess the uterine muscle and distinguish between different types of uterine abnormalities. Imaging findings are interpreted alongside symptoms and examination results rather than in isolation.
Blood tests and other investigations
If menstrual bleeding is heavy or prolonged, blood tests may be used to check for anemia, which can develop when the body loses too much blood over time. Depending on the symptoms, a clinician may also consider other causes of pelvic pain or abnormal bleeding, including endometriosis, ovarian conditions, infection, or pregnancy-related problems.
For more information on investigating fibroids, consult Mayo Clinic's fibroid diagnostic guidance. The tests recommended for any individual depend on the symptoms, examination findings, and initial imaging results.
What treatments can help pelvic pain?
Treatment depends on the cause of the symptoms, their effect on daily life, medical history, and whether pregnancy is desired in the future. Not everyone needs treatment. If symptoms are manageable and there are no concerning findings, monitoring may be appropriate. When pain or bleeding is disruptive, a healthcare professional can discuss options aimed at relieving symptoms or treating the underlying condition.
Managing adenomyosis
Treatment options may include anti-inflammatory pain medicines, hormonal contraception, or a hormone-releasing intrauterine system to reduce menstrual pain and bleeding. The choice depends on individual health factors, preferences, and treatment goals. If symptoms remain troublesome despite other approaches, surgery may be considered. Hysterectomy, which removes the uterus, is a definitive treatment for adenomyosis in people who do not wish to carry a pregnancy in the future.
Managing fibroids
Fibroid treatment may involve monitoring, medicines to manage bleeding or pain, or procedures to reduce or remove the growths. Options can include myomectomy, which removes fibroids while leaving the uterus in place, and uterine artery embolization, which reduces their blood supply. Hysterectomy is another option for selected people. The most appropriate approach depends on fibroid size and location, symptom burden, overall health, and future pregnancy plans.
How does future pregnancy affect treatment choices?
Pregnancy plans are important when comparing treatment options. Some procedures can affect the ability to become pregnant or carry a pregnancy, and not all treatments are suitable for people who want to preserve fertility. A clinician can explain the likely benefits, limitations, and risks of each option, including whether treatment may need to be adjusted to support future reproductive goals.
When should pelvic pain be assessed?
Arrange a medical appointment if pelvic pain keeps returning, periods become increasingly painful or heavy, bleeding occurs between periods or after sex, or symptoms interfere with work, sleep, exercise, or everyday activities. Persistent abdominal fullness or new urinary or bowel symptoms also deserve assessment, particularly if they are unexplained or worsening.
Seek urgent medical care for sudden or severe pelvic pain, especially when accompanied by fainting, marked dizziness, fever, vomiting, or heavy bleeding. If pregnancy is possible, pelvic pain with bleeding or faintness needs prompt assessment because pregnancy-related complications can cause similar symptoms. Do not assume that new or intense pain is caused by a previously identified fibroid or adenomyosis.
Keeping a record of pain timing, menstrual dates, bleeding amount, and other symptoms can help make an appointment more useful. Note any medicines you take and whether they help. This information can help your healthcare professional decide which examinations or tests are appropriate.