Bladder Endometriosis

Bladder endometriosis happens when tissue similar to the lining of the uterus grows on or inside the bladder. This misplaced tissue can irritate the bladder and cause pain, frequent urination, or blood in the urine, especially around the menstrual cycle. While this condition is less common than other forms of endometriosis, it can significantly impact daily life.

Experts have not fully figured out the exact cause, but they believe several factors may play a role. Retrograde menstruation, where menstrual blood flows backward into the pelvis, is one possible explanation. Some believe genetic, immune, or hormonal factors allow this tissue to attach and grow in the bladder.

Definition of Symptom

A symptom is a noticeable change in the body that signals a possible health problem. It is what a person feels or experiences, even if it cannot be directly measured by a test.

In bladder endometriosis, symptoms often overlap with other endometriosis symptoms. These may include pelvic pain, abdominal pain, or lower back pain, especially around menstruation. Common signs and symptoms of bladder endometriosis include:

• Bladder pain or discomfort when urinating
• Frequent urination or urgency
• Blood in urine during or after periods
• Pain that worsens during periods

Other symptoms linked to endometriosis may appear at the same time. These include chronic pelvic pain, heavy menstrual periods, bloating, constipation, nausea, and fatigue.

Symptom	Possible Link to Bladder Endometriosis
Bladder pain	Endometrial tissue on or in the bladder
Painful urination	Irritation of bladder wall
Pelvic or abdominal pain	Shared with general endometriosis pain
Constipation, bloating	Pressure on nearby organs
Fatigue, nausea	Common with chronic pain conditions

Symptoms can range from mild discomfort to severe pain that interferes with daily life. They often worsen during menstruation but may also occur outside of menstrual cycles. This overlap makes diagnosis more difficult, since bladder conditions can mimic other urinary disorders.

Possible Causes/Diseases Condition

Bladder endometriosis develops when tissue similar to the uterine lining grows on or inside the bladder. This tissue responds to hormonal changes during the menstrual cycle. Over time, these growths can irritate or invade the bladder wall.

One widely discussed explanation is retrograde menstruation. In this process, menstrual blood flows backward through the fallopian tubes into the pelvic cavity. Cells from the uterine lining may then attach to the bladder or other urinary tract structures. Other possible risk factors include:

• Genetics: Having a family history of endometriosis may increase risk.
• Hormonal Influence: Higher levels of estrogen can encourage tissue growth.
• Immune System Changes: If the body cannot clear misplaced tissue, it may allow it to grow.

Bladder endometriosis can appear as tissue on the bladder surface or deeper growth into the bladder muscle. The severity depends on how far the tissue spreads and how much is affected.

In some cases, bladder involvement happens with other forms of pelvic endometriosis. This overlap can make diagnosis harder, as symptoms may mimic urinary infections or other bladder conditions.

This condition is considered a subtype of urinary tract endometriosis, which can also affect the ureters or kidneys. While bladder involvement is less common, it may cause more direct urinary symptoms compared to tissue found elsewhere in the pelvis.

Other Non-Disease Causes

Not all bladder pain or urinary symptoms linked to endometriosis come from the disease itself. Everyday factors and natural body changes can also play a role.

• Menstrual cycle changes can affect bladder sensitivity. Hormone levels, especially progesterone, may influence how the bladder responds to pressure or irritation. Some people notice more discomfort during certain phases of their cycle.
• Hormone therapy and birth control pills may also change bladder symptoms. These treatments adjust hormone levels to manage endometriosis, but they can sometimes cause side effects like urinary frequency or mild irritation.
• Infections such as a urinary tract infection (UTI) can mimic endometriosis-related bladder pain. A UTI often causes burning, urgency, and frequent urination, which overlap with bladder endometriosis symptoms.
• A history of pelvic inflammatory disease (PID) may leave behind scarring or irritation in the pelvic area. Even after treatment, these changes can contribute to urinary discomfort that is not directly caused by endometriosis.
• Menopause brings lower estrogen levels, which can thin bladder and urethral tissues. This natural change may increase bladder sensitivity or dryness, leading to symptoms similar to bladder endometriosis.

Factor	How It May Affect the Bladder
Menstrual cycle	Hormone shifts increase sensitivity
Hormone therapy	Alters hormone balance and may affect urination
Birth control pills	Can reduce or change bladder symptoms
UTI	Causes pain and urgency and mimics endometriosis
PID	Scarring or irritation near urinary tract
Menopause	Tissue thinning and bladder sensitivity

How It Causes the Symptom

Bladder endometriosis occurs when tissue similar to the uterine lining grows on or inside the bladder wall. This misplaced tissue reacts to hormonal changes during the menstrual cycle, which can lead to swelling, irritation, and bleeding. These changes often cause urinary symptoms such as:

• Pain or burning during urination
• Blood in the urine (especially around menstruation)
• Frequent or urgent need to urinate

When the tissue grows deeper into the bladder wall, it can disrupt how the bladder stores and releases urine. This may explain why some people feel constant pressure or pain in the pelvic area. Doctors may check for tenderness or masses with a pelvic exam, but this alone often cannot confirm bladder endometriosis.

A cystoscopy can help by allowing doctors to see the bladder lining and check for growths. Sometimes, doctors use laparoscopy to look inside the abdomen and pelvis. This procedure provides a clearer view of the bladder surface and surrounding organs. If needed, doctors can remove or treat the growths during the same procedure.

Because the tissue responds to hormones, symptoms often worsen during menstruation. The bladder cannot shed this tissue like the uterus does, so it builds up and irritates the bladder instead. This cycle of inflammation leads to many of the painful and disruptive symptoms.

Possible Complications

Bladder endometriosis can lead to several complications that affect both urinary and reproductive health. These complications may vary in severity depending on how much tissue has spread and how deeply it has grown.

Urinary problems are among the most common. People may experience frequent urination, pain while urinating, or blood in the urine. In some cases, scar tissue can narrow the urinary tract, making it harder for the bladder to empty fully.

Adhesions and scar tissue may develop as the body reacts to endometrial growths. These can bind the bladder to nearby organs, such as the uterus or bowel, leading to pelvic pain and reduced organ function. Adhesions can also make surgery more complex if treatment is needed.

Infertility can occur when bladder endometriosis exists alongside pelvic endometriosis. Adhesions around the reproductive organs may block or distort the fallopian tubes, while inflammation may interfere with egg release or implantation. Other possible complications include:

• Recurrent infections may occur due to incomplete bladder emptying.
• Ureter involvement may affect kidney function if tissue blocks urine flow.
• Chronic pelvic pain often worsens during menstruation.

When to Seek Medical Attention

Bladder endometriosis can cause symptoms similar to other conditions, so it’s important to know when to seek medical care. Contact a doctor if you notice persistent pelvic pain, especially if it gets worse during menstruation. Don’t ignore pain that disrupts daily activities. Watch for urinary symptoms such as:

• Frequent urination
• Urgency to urinate
• Pain or burning when urinating
• Blood in the urine

If you also experience bowel changes like constipation or diarrhea along with bladder issues, see a doctor, as these signs may point to other overlapping conditions. Seek immediate care if you have:

• Severe pelvic pain that does not improve with over-the-counter medicine
• Trouble emptying your bladder
• Blood in your urine outside of menstruation

Ignoring these symptoms can delay diagnosis and make treatment harder. A doctor can order tests to find the cause and recommend the best next steps.