Adenomyosis

What happens in adenomyosis

The uterus has two main layers: the inner lining (endometrium), which builds up and sheds each month, and the thick muscle wall (myometrium). In adenomyosis, islands of endometrial tissue sit deep inside the muscle. They respond to hormones just like the normal lining, thickening and bleeding each cycle, but the blood has nowhere to go. This causes inflammation, swelling and thickening of the muscle around them.

The result is a globular, enlarged uterus, often two to three times normal size, that contracts abnormally and is tender. Adenomyosis can be:

• Diffuse: spread throughout the uterine wall
• Focal (adenomyoma): a localized nodule that can look like a fibroid

Symptoms

• Heavy menstrual bleeding with clots, often lasting longer than 7 days. See heavy menstrual flow.
• Severe period cramps (painful menstruation) that may start before bleeding and worsen over the years
• Chronic pelvic pain or pressure between periods
• Painful intercourse, especially deep pain
• Bloating and a feeling of fullness in the lower belly
• Fatigue and breathlessness from iron deficiency anemia due to blood loss
• Difficulty conceiving or pregnancy loss in some women

Symptoms usually ease after menopause, when estrogen levels fall.

Causes and risk factors

The exact cause is unknown. Leading theories are that the boundary between lining and muscle is disrupted, allowing lining cells to invade, or that tissue develops in the muscle from early stem cells. Risk factors include:

• age 35 to 50
• having had children, especially several pregnancies
• previous uterine surgery, including cesarean section, D and C or fibroid removal
• early first period and short cycles
• high estrogen exposure
• having endometriosis or fibroids

Adenomyosis vs endometriosis vs fibroids

The three often occur together, so one diagnosis does not exclude another.

Diagnosis

A doctor may feel an enlarged, tender uterus during a pelvic exam. Imaging is the main tool:

• Transvaginal ultrasound: shows a bulky, asymmetric uterus, thickened walls, small cysts within the muscle and a fuzzy junction between lining and muscle.
• MRI: the most accurate imaging test. A thickened junctional zone of 12 mm or more strongly suggests adenomyosis.
• Blood count and iron studies for anemia.
• Endometrial biopsy in women over 45 or with risk factors, to rule out abnormal changes in the lining.

A definite diagnosis can only be made by examining the uterus after hysterectomy, but imaging is now reliable enough to guide treatment.

Treatment

Treatment depends on symptoms, age and whether you want future pregnancies.

Pain relief

• NSAIDs such as ibuprofen or naproxen, started a day before or at the start of a period, following the label dose. They reduce both pain and bleeding.

Hormonal treatments

• Levonorgestrel intrauterine device (hormonal IUD): very effective at reducing heavy bleeding and pain in adenomyosis, lasting several years.
• Combined birth control pills, patch or ring, often taken continuously to skip periods.
• Progestin-only treatments: pills such as dienogest or norethindrone, or injections.
• GnRH agonists or antagonists (sometimes with add-back hormone therapy): create a temporary menopause-like state, shrinking the uterus. Used short term or before surgery.

Non-hormonal medicines

• Tranexamic acid taken during periods reduces bleeding by about a third to a half.
• Iron supplements for anemia.

Procedures

• Uterine artery embolization: blocks the blood supply to the affected tissue through a catheter in the groin. It improves symptoms for many but is usually not advised if you want to become pregnant.
• Endometrial ablation: destroys the lining. It can help bleeding in mild superficial adenomyosis but often fails in deeper disease.
• High-intensity focused ultrasound (HIFU) and radiofrequency ablation: less widely available options for focal disease.
• Adenomyomectomy: surgical removal of a focal adenomyoma while keeping the uterus, in specialized centers.
• Hysterectomy: removal of the uterus is the only definitive cure. The ovaries can usually be kept.

Adenomyosis and fertility

Adenomyosis is linked to lower IVF success, higher miscarriage risk and some pregnancy complications such as preterm birth. Many women with adenomyosis still conceive. A fertility specialist may recommend a period of GnRH treatment before embryo transfer.

Outlook

Adenomyosis is benign and not linked to cancer. Symptoms can usually be controlled with medicines or an IUD until menopause, after which they typically resolve. For those who have finished having children and have severe symptoms, hysterectomy brings lasting relief.

Frequently asked questions

What are the main symptoms of adenomyosis?

The main symptoms are heavy, prolonged periods with clots, severe menstrual cramps that worsen over time, chronic pelvic pain, pain during sex and a bloated lower belly. Some women have few or no symptoms, and the condition is found on a scan.

What is the difference between adenomyosis and endometriosis?

In adenomyosis, endometrial-like tissue grows inside the muscle wall of the uterus. In endometriosis, it grows outside the uterus, on the ovaries, pelvic lining or bowel. Both cause painful periods and can occur together, but adenomyosis more often causes heavy bleeding and an enlarged uterus.

How is adenomyosis treated?

Treatment includes NSAIDs, tranexamic acid, hormonal IUDs, birth control pills, progestins and GnRH medicines. For persistent symptoms, options include uterine artery embolization or focused ablation. Hysterectomy is the only permanent cure and is considered when pregnancy is no longer wanted.

Can adenomyosis cause infertility?

It can reduce fertility and is linked to lower IVF success and a higher risk of miscarriage, but many women with adenomyosis conceive naturally or with treatment. A fertility specialist can tailor treatment, sometimes using hormone suppression before IVF.

Does adenomyosis go away after menopause?

Usually, yes. Because adenomyosis depends on estrogen, symptoms typically fade after menopause, and the uterus may shrink. Bleeding after menopause is not normal and should always be checked.