Endometriosis is a condition where tissue resembling the uterus lining grows outside the uterus, such as on the ovaries or fallopian tubes. With bladder endometriosis, this tissue grows inside or on the surface of the bladder.

Bladder endometriosis is a rare form of the condition that can cause severe discomfort. When it forms only on the surface of the bladder, it is called superficial endometriosis, and if it develops inside the bladder lining or wall, it is called deep endometriosis.

During regular menstruation, endometrial tissue thickens and exits the body in the blood. However, when the tissue grows outside of the uterus, it cannot leave through the vagina, so it remains inside the body. This results in symptoms such as painful and heavy periods.

In this article, we look at the symptoms, diagnosis, and treatment of bladder endometriosis. We also discuss other forms of bladder pain and interstitial cystitis, which can have similar symptoms to bladder endometriosis.

Prevalence

Endometriosis affects 6 to 10 percent of women during their reproductive years. The majority of women, therefore, receive their diagnosis during this time with the average age being 27 years.

Bladder endometriosis is rare. A 2014 study reports that as few as 1 to 2 percent of women with endometriosis may have endometrial growths in their urinary system, and the bladder is the organ most likely to be affected.

Symptoms

Person with bladder endometriosis doubled over holding lower abdomen in pain.
Pain when the bladder is full and the need to urinate frequently, are common symptoms of bladder endometriosis.

A 2012 study found that around 30 percent of women who have bladder endometriosis experience no symptoms. A person may not be aware that they have the condition until it shows up as a result of tests they have for another reason, such as suspected infertility.

A woman is more likely to notice any symptoms of endometriosis around the time she is due to have her period.

Symptoms of bladder endometriosis specifically may include:

  • feeling the need to urinate urgently
  • frequent urination
  • pain when the bladder is full
  • burning or painful sensations when passing urine
  • blood in the urine
  • pelvic pain
  • lower back pain (on one side)

When endometriosis develops in other parts of the pelvis, symptoms may include:

  • cramping and pain before and during periods
  • pain when having sex
  • bleeding during or between periods that may be heavy
  • feeling extremely tired
  • nausea
  • diarrhea

Diagnosis

Ultrasound technician with equipment.
An ultrasound may be performed to find out where the endometrial tissue has formed.

To diagnose bladder endometriosis, a doctor will initially check the vagina and bladder to ascertain whether there are any abnormal growths. They will also usually do a urine test to check for blood in the urine.

Other tests that a doctor may conduct include:

  • An ultrasound. An ultrasound involves using high-frequency sound waves to create pictures of the inside of the body. A doctor will find out where the endometrial tissue is growing and how much there is.
  • An MRI scan. An MRI scan uses magnets and radio waves to produce detailed images of the inside of a person’s body. A doctor will use this test to look for endometriosis in the bladder as well as other parts of the pelvis.
  • A cystoscopy. To perform a cystoscopy, a doctor will insert a scope through the urethra. Doing this will allow them to look at the bladder lining to see whether any endometrial tissue is growing there.

Stages of endometriosis

Once a diagnosis of endometriosis is confirmed, the doctor will see what stage the condition is at. Stages are defined according to how much tissue is present and how deeply it has grown into the person’s organs.

There are four stages which are:

Stage 1. Minimal. A person with stage 1 endometriosis only has small amounts of the tissue growing, and it is only found on the surface or around the organs.

Stage 2. Mild. A person with stage 2 endometriosis has more extensive tissue growths, but they are still on the surface of the organs rather than inside them.

Stage 3. Moderate. A person with stage 3 endometriosis has more widespread tissue, which has begun to grow inside the pelvic organs.

Stage 4. Severe. A person with stage 4 endometriosis has lots of endometrial tissue, which is growing inside several of the pelvic organs.

Treatment

There is no current cure for endometriosis. However, the condition can be managed through medication and sometimes surgery.

Surgery is the most common treatment for those with bladder endometriosis. During surgery, a doctor will try to remove all of the tissue growing in the bladder, and this should help relieve symptoms.

There are two types of surgery used for bladder endometriosis:

  • Transurethral surgery is where a doctor inserts a thin scope inside the urethra and bladder. The scope has a cutting tool at the end of it, which is used to cut off the endometrial tissue.
  • Partial cystectomy involves removing an affected part of the bladder. A surgeon can either carry out a laparotomy, which involves one large incision, or a laparoscopy, where the surgeon will need to make several smaller incisions.

Doctors will likely prescribe hormone treatments to help slow the growth of endometrial tissue or manage pain. Hormone treatments may include gonadotropin-releasing hormone (GnRH) or birth control pills.

Fertility

Bladder endometriosis does not have any effect on a woman’s fertility. However, endometrial tissue often grows in parts of a woman’s reproductive system such as the ovaries, which may affect a woman’s likelihood of conception.

Bladder endometriosis vs. interstitial cystitis

Female doctor in discussion with female patient.
Interstital cystitis has similar symptoms to bladder endometriosis.

A person with interstitial cystitis may experience many of the same symptoms as those with bladder endometriosis. Both conditions can cause:

  • chronic pelvic pain that lasts 6 months or more
  • needing to urinate frequently and urgently
  • pain during sex
  • needing to urinate at night
  • pain in the bladder
  • symptoms affected by the menstrual cycle

A person who does not respond to typical endometriosis treatments may, in fact, have undiagnosed interstitial cystitis. It is possible for a person to have both conditions.

The exact cause of interstitial cystitis is not known. Unfortunately, antibiotics, which can treat other types of cystitis, are not effective.

Recommended treatment usually involves lifestyle changes, such as making dietary changes, stopping smoking, drinking less before bedtime, and scheduling planned toilet breaks to ensure the bladder does not get too full.

Bladder endometriosis vs. other bladder pain

Other possible causes for a person to feel discomfort or pain in their bladder include:

  • an infection in the bladder
  • a defect in the bladder’s lining
  • an autoimmune reaction
  • an allergic reaction

If a person experiences bladder pressure or pain that does not go away, they should make an appointment with their doctor. The doctor will be able to perform tests to find out the cause.

Possible causes

Doctors are not sure of the exact cause of bladder endometriosis. Possible reasons include:

  • Pelvic surgery. One theory is that a previous surgery, such as a cesarean delivery or a hysterectomy, can introduce endometrial cells into the bladder.
  • Early cell transformation. This occurs when leftover cells from an embryo turn into endometrial tissue.
  • Retrograde menstruation. With retrograde menstruation, a woman’s menstrual blood flows backwards into the pelvis instead of flowing out of the body. The endometrial cells may then implant into the bladder wall.
  • Transplantation. Transplantation is where the endometrial cells move through the lymph system or blood vessels and end up in a person’s bladder.
  • Genetics. Endometriosis is thought to be hereditary.

Outlook

Without proper treatment, bladder endometriosis can cause kidney damage. It is also possible for cancerous tissue to grow from endometrial tissue in the bladder, though this is very rare.

A person’s outlook depends on which stage of endometriosis they have. More severe cases are more difficult to treat.

Surgery to remove the tissue is often the most effective treatment, though endometriosis often returns after surgery. Multiple surgeries may therefore be required.