Asherman's syndrome: scar tissue inside the womb

Asherman’s syndrome in plain language

The cavity of the womb is normally a smooth, open space lined by the endometrium, the lining that thickens and is shed each month. In Asherman’s syndrome, bands of scar tissue (intrauterine adhesions, also called synechiae) form inside the cavity and join its walls together. Depending on how extensive they are, the adhesions may affect a small area or close off much of the cavity, and the lining in the scarred areas may be thin or damaged.

Asherman’s syndrome usually follows damage to the base layer of the lining, from which the lining regrows each month. It most often follows surgery to the lining soon after a pregnancy, such as surgical management of a miscarriage or removal of placental tissue after birth ^[1]. It can also follow other operations inside the womb, a caesarean section, or infection. Sometimes no clear cause is found.

Symptoms

• periods that become much lighter, or stop altogether, after surgery or a pregnancy
• cyclical pelvic pain without bleeding, when blood is trapped behind the scar tissue
• difficulty conceiving
• miscarriage, including recurrent miscarriage
• in pregnancy, a higher chance of problems with the placenta

Some women have no symptoms, and the adhesions are found during investigations for fertility or after failed embryo transfers.

How I assess Asherman’s syndrome

I start with a careful history, including any previous pregnancies and procedures inside the womb, and your plans for a family. At Parkside Hospital and the CRP Clinic I can perform an ultrasound scan during the consultation, often including a three-dimensional view of the cavity, so we can usually discuss the findings at the same visit. The scan shows the thickness and pattern of the lining and can suggest where adhesions lie.

A hysteroscopy (looking inside the womb with a slim telescope) confirms the diagnosis and shows how extensive the scarring is; the specialist societies for this kind of surgery regard it as the most reliable test ^[1]. When the scan already points clearly to adhesions, I usually plan a hysteroscopy at which I can both confirm and treat them.

If you have scans, hysteroscopy reports or photographs from elsewhere, please bring them or send them to my practice manager, Helen, before your appointment.

Treatment options

I will explain every reasonable option, including no treatment, and then we decide together. If the adhesions are causing no symptoms and you are not planning a pregnancy, leaving them alone may be the right option for you. For most women with symptoms, or who hope to conceive, the treatment is surgery to divide the scar tissue and restore the shape of the cavity.

Hysteroscopic division of adhesions

I divide the scar tissue by hysteroscopy, through the cervix, so there are no incisions on the abdomen. Using fine instruments passed through the hysteroscope, I separate the walls of the cavity, cutting the bands of scar tissue while preserving as much healthy lining as possible.

When the adhesions are dense, or much of the cavity is closed, I use ultrasound guidance during the procedure. The ultrasound shows the outline of the womb and the thickness of its wall as I work, which helps me to guide the procedure and reopen the cavity as safely as possible. I prefer it to watching from inside the abdomen with a laparoscope, which shows the outside of the womb but not its wall.

After the procedure

Preventing the adhesions from forming again is as important as dividing them. I routinely place an anti-adhesion gel (hyaluronic acid gel) in the cavity at the end of the procedure, to keep its walls apart while the lining heals.

A Cochrane review of the randomised trials found fewer adhesions at a second look when a gel, a device or hormone treatment was used: about one woman in nine was spared new adhesions. The trials were small and the evidence is graded as weak, and whether it improves the chance of a baby has not been shown ^[2]. Depending on the severity, I may also recommend:

• a course of hormone treatment while the lining heals, which is sometimes suggested; we will talk about whether it is right for you
• a second-look hysteroscopy a few weeks later, to check healing and divide any new adhesions while they are still soft
• in some cases, a temporary device placed in the cavity to keep its walls apart

What to expect from treatment

The outcome depends mainly on how severe the scarring was and how well the lining recovers. For mild and moderate adhesions, one procedure is usually enough and many women go on to conceive. Severe Asherman’s syndrome is more difficult to treat, more than one procedure may be needed, and the chance of a successful pregnancy is lower.

The specialist societies’ guideline puts the chance of adhesions returning at between about 1 in 30 and 1 in 4 after mild or moderate disease, and between about 1 in 5 and 3 in 5 after severe disease ^[1]. I will talk with you about what is realistic in your case.

I check the lining with a scan once it has had time to heal, and then we decide together when to start trying for a pregnancy or go ahead with embryo transfer.

In one published series, from two Australian hospitals, 124 women wanted a baby after treatment: about eight in ten became pregnant and about six in ten had a baby, although this was a single team looking back at its own results ^[3].

A pregnancy after treatment for Asherman’s syndrome carries a higher chance of complications, particularly problems with the placenta, including the placenta growing too deeply into the wall of the womb: in that series about one birth in six was affected by a placental problem, and about three in ten babies were born early ^[3].

I will make sure your obstetric team knows your history so that your pregnancy can be monitored appropriately.

What the procedure involves and recovery

The procedure is usually carried out as a day case, under general anaesthetic or sedation, and takes between fifteen minutes and an hour depending on the extent of the scarring. You will receive full written information beforehand.

Afterwards, mild cramping and light bleeding for a few days are normal. Most women return to work within a day or two. The main risks are infection, bleeding, perforation of the wall of the womb (which is uncommon and usually heals on its own, although it occasionally needs a laparoscopy to check for injury to nearby organs) and the adhesions forming again.

I see you afterwards to go through what I found and to plan the next steps, and my letter follows to you and your fertility team.

Listen: Asherman’s syndrome on The Fertility Suite podcast

I talked about Asherman’s syndrome, and about endometriosis, with Rachel Sherriff on The Fertility Suite podcast in February 2024: how scarring inside the womb can follow treatment for a miscarriage, how it is recognised and treated, and what it means for fertility. Listen to the episode.