Asherman syndrome is a condition in which scar tissue forms inside the uterus, sometimes also affecting the cervix. This scar tissue, known as intrauterine adhesions or synechiae, builds up on the walls of the uterus, which can reduce the size of the uterine cavity and, in some cases, block it entirely. Common symptoms include reduced or absent menstrual flow, pelvic pain, infertility, and repeated miscarriages.

The exact prevalence of Asherman syndrome in the United States is unknown. Some people who have intrauterine adhesions have mild or even no symptoms and may go undiagnosed.

Studies have found that intrauterine adhesions are present in about 1.5% of women who undergo a hysterosalpingogram (HSG), an X-ray of the uterus and fallopian tubes, to evaluate infertility. Up to 21.5% of women with a history of dilation and curettage (D&C) have these adhesions, as do between 5% and 39% of women with recurrent miscarriages. (D&C is a medical procedure in which the endometrium, the inner lining of the uterus, is removed or scraped away.) The risk of developing Asherman syndrome increases with repeated uterine procedures, especially after pregnancy-related surgeries such as D&C.

Asherman syndrome can often be managed successfully with treatment, and many women experience improvement in symptoms and fertility after undergoing treatment. With surgery and measures to prevent recurrence, most individuals with Asherman syndrome can look forward to restored menstrual function, reduced symptoms, and the possibility of pregnancy. Hormonal therapies are also effective in some cases, and stem cell treatment is a new treatment possibility.

Asherman syndrome is a condition in which scar tissue, called adhesions or synechiae, forms inside the uterus and sometimes the cervix. In a healthy uterus, the inner lining, known as the endometrium, thickens and sheds each month during the menstrual cycle, allowing for normal periods and creating an environment where a fertilized egg can implant and grow. In Asherman syndrome, scar tissue builds up on the walls of the uterus, which can distort the shape of the uterus and reduce the size of the uterine cavity.

These adhesions can range from thin, filmy bands to dense, thick scar tissue. The extent of the adhesions determines the severity of the condition. When the scar tissue is mild, it may only involve a small part of the uterus and cause few or no symptoms. In more severe cases, the adhesions can cover most of the uterine cavity, leading to absent or very light periods, pelvic pain, infertility, or repeated miscarriages. The scar tissue can also block the cervix, preventing menstrual blood from leaving the body and sometimes causing pain or other complications.

Asherman syndrome can affect any woman, especially those who have had surgical procedures involving the uterus. The condition can significantly impact menstrual health and fertility. Most women who have Asherman syndrome are diagnosed during evaluation for changes or pain around their menstrual cycle or difficulty becoming pregnant.

Asherman syndrome is most commonly caused by trauma to the lining of the uterus, which occurs during surgical procedures such as D&C. D&C is often performed to remove tissue from the uterus after a miscarriage, abortion, or to treat certain uterine conditions like heavy bleeding or retained placental tissue after childbirth. The risk of developing Asherman syndrome increases with repeated D&C procedures, particularly when performed soon after pregnancy, as recent pregnancy makes the uterus more vulnerable to injury. Other types of surgery on the uterus, such as removal of fibroids or polyps, repair of structural defects, or procedures following cesarean section, can also lead to scar tissue formation and increase the risk of Asherman syndrome.

Inflammation in the uterus, such as from endometriosis or pelvic inflammatory disease, has also been linked to the development of intrauterine adhesions. Infections such as genital tuberculosis or parasitic infections like schistosomiasis can cause inflammation in the uterus, leading to the buildup of scar tissue. These infections are rare in the U.S.

Although surgical trauma is a main cause of Asherman syndrome, only a small portion of women who undergo a D&C or other uterine surgery develop Asherman syndrome. In addition, some people develop Asherman syndrome without any clear preceding injury or procedure. This may be due to individual differences in susceptibility. However, this condition is not genetic and does not run in families.

Overall, any event or condition that damages the inner layer of the uterus and leads to inflammation or scarring can potentially cause Asherman syndrome.

Risk factors for Asherman syndrome include:

• D&C, especially after pregnancy loss or retained placental tissue
• Repeated uterine procedures or surgeries
• Curettage performed soon after pregnancy or childbirth to remove tissue from the uterus
• Surgical removal of fibroids or polyps
• Cesarean section (C-section)
• Uterine artery embolization
• Use of B-Lynch sutures (used to stop hemorrhage after childbirth)
• Surgical treatment of Müllerian anomalies (a group of disorders affecting the female reproductive system)
• Pelvic inflammatory disease (PID), an infection of the female reproductive organs
• Endometriosis, a condition in which the endometrium grows outside the uterus
• Genital tuberculosis
• Infection with schistosomiasis, a parasitic infection
• Problems with the placenta, such as placenta accreta, a condition in which the placenta attaches too deeply into the uterine wall
• Pelvic radiation therapy (for example, to treat cancer)

Symptoms of Asherman syndrome may include:

• Absent menstrual periods (amenorrhea)
• Light or reduced menstrual flow (hypomenorrhea)
• Irregular menstrual cycles
• Increased cramping or pelvic pain
• Cyclic pelvic pain or painful menstruation (dysmenorrhea)
• Infertility
• Repeated miscarriages or recurrent pregnancy loss
• Painful periods with little or no bleeding
• Buildup of menstrual blood trapped in the uterus due to scarring or blockage (called hematometra)
• Backward flow of menstrual blood into the fallopian tubes (called retrograde menstruation)

To diagnose Asherman syndrome, your doctor will review your medical history, conduct a physical exam, and order one or more diagnostic tests.

Your doctor may ask about your menstrual cycle, symptoms such as changes in menstrual flow or pelvic pain, history of infertility or repeated miscarriages, and any previous uterine procedures or surgeries. During the physical exam, your doctor may look for signs of menstrual abnormalities or pelvic tenderness, though a pelvic exam often does not reveal problems.

Additional tests are necessary to make a diagnosis, including:

• Hysteroscopy: This is the gold standard for diagnosing Asherman syndrome. A thin, lighted camera (hysteroscope) is inserted through the cervix into the uterus, allowing direct visualization of the uterine cavity and any scar tissue or adhesions. Hysteroscopy also allows treatment at the same time.
• Saline infusion sonohysterography (SIS): This imaging test uses ultrasound along with saline to fill and expand the uterine cavity, making it easier to detect adhesions or abnormal shapes inside the uterus.
• Hysterosalpingography (HSG): This test involves injecting a contrast dye into the uterus and taking X-ray images to look for filling defects or irregularities caused by adhesions.
• Transvaginal ultrasound: This test uses sound waves to create images of the uterus and can sometimes show areas of scarring or changes in the endometrial lining, but it is less sensitive than other methods.
• Magnetic resonance imaging (MRI): MRI may be used in rare cases when the uterine cavity is completely blocked or when other imaging tests are inconclusive.
  

In some cases, blood tests or laboratory examinations may be ordered to check for infections such as tuberculosis or schistosomiasis if these are suspected causes.

Most cases of Asherman syndrome can be managed effectively. Treatment aims to restore the normal shape and function of the uterine cavity, relieve symptoms, and improve menstruation and fertility.

The main treatments include:

• Hysteroscopic surgery: This is the primary treatment for Asherman syndrome. A hysteroscope is inserted through the cervix into the uterus, allowing the doctor to see and carefully cut or remove the scar tissue or adhesions. This procedure is often done in an outpatient setting.
• Physical barriers to prevent re-adhesion: After surgery, devices such as a Foley catheter (a small balloon) are placed inside the uterus for several days to keep the uterine walls apart while healing, reducing the risk of new adhesions forming. Inserting an intrauterine device (IUD) at the time of surgery may also reduce the risk of new adhesions.
• Hormone therapy: Your doctor may prescribe estrogen before or after surgery to help the uterine lining heal and regenerate. This therapy can promote tissue repair and support the return of normal menstrual cycles.
• Antibiotics: If there is evidence of infection, antibiotics may be given to prevent or treat infection and reduce inflammation that could lead to new scar tissue.
• Anti-adhesive gels or barriers: In some cases, special gels or membranes may be applied inside the uterus after surgery to help prevent the recurrence of adhesions, though evidence for their effectiveness is mixed.
• Experimental therapies: For severe or recurrent cases, stem cell therapy and platelet-rich plasma are being studied as ways to help regenerate the uterine lining, but these treatments are still experimental and not widely available.

Treatment depends on the severity of the adhesions, the patient’s symptoms, and their desire for future fertility. Most people experience improvement in symptoms and menstrual function after treatment, though some may need more than one procedure.

People with Asherman syndrome may be at increased risk for certain complications, including:

• Infertility, or difficulty becoming pregnant
• Recurrent miscarriages
• Menstrual abnormalities, such as absent or very light periods
• Pelvic pain or cramping, sometimes due to blocked menstrual flow
• Buildup of menstrual blood trapped in the uterus because of scarring or blockage (called hematometra)
• Obstetric complications, such as preterm labor (early delivery), low birth weight, retained placenta (when the placenta does not deliver after childbirth), and problems with the placenta
• Postpartum hemorrhage, or heavy bleeding after childbirth
• Recurrence of scar tissue after treatment
• Need for repeat surgical procedures to remove new or persistent adhesions
• Uterine perforation (a hole in the wall of the uterus) or infection, which are rare complications of surgery

The outlook for people with Asherman syndrome can vary depending on the severity of the adhesions, the extent of damage to the uterine lining, the presence of other health conditions, and whether the person wishes to become pregnant. Treatment can restore the shape and function of the uterus for many people with Asherman syndrome. Some people may need more than one procedure, as scar tissue can return. In general, most people experience improvement in menstrual flow and relief of symptoms after treatment, especially when the adhesions are mild or moderate. Restoration of normal menstrual cycles is possible in most cases, and many people can conceive after treatment. However, even after successful treatment, women with Asherman syndrome have an increased risk of pregnancy complications, such as miscarriage, preterm labor, and low birth weight. The risk is highest for people with severe cases of Asherman syndrome.

With careful management and follow-up, many people with Asherman syndrome are able to achieve their reproductive goals and maintain good quality of life.

“At Yale, we provide comprehensive care for women with Asherman syndrome,” says Hugh Taylor, MD, chair of the Department of Obstetrics, Gynecology & Reproductive Sciences. “We have experts in surgical and hormonal treatment as well as the most advanced fertility care. We also have multiple faculty who conduct groundbreaking research on Asherman syndrome. We were the first to discover the role of stem cells in repairing the uterus and we have an ongoing clinical trial, which is the first in the United States to use stem cell-based therapy for Asherman syndrome.”