Mr Adrian Lower, Consultant Gynaecologist
Understanding Asherman’s Syndrome
Asherman’s syndrome is the condition that occurs when scar tissue caused by a surgical procedure forms on the lining of the uterus often resulting in infertility. One of the few experts in the treatment of Asherman’s syndrome, Consultant Gynaecologist Mr Adrian Lower, explains in detail what causes this condition and how it should be treated.
What is Asherman’s Syndrome?
Few people have heard of Asherman’s syndrome and although many health professionals believe it to be quite rare, it affects a significant number of women who have had a dilation and curettage (D&C). A D&C is a surgical procedure that involves widening the cervix and removing the tissue lining (endometrium) of the uterus. Damage to the inner wall of the uterus leads to adhesions (scar tissue), which cause the tissues to stick together and can block the cervix. This reduces menstrual flow or stops periods altogether and often means that the woman is then infertile until and unless the adhesions are removed.
What causes Asherman’s syndrome?
In most women who develop Asherman’s syndrome the trigger is physical damage sustained during a dilation and curettage procedure (D&C). Adhesions are more extensive if there is also an infection. A D&C is recommended for women of child bearing age in several circumstances:
- After childbirth to remove a retained placenta
- To stop excessive bleeding after birth
- After a termination of pregnancy
- After a miscarriage to reduce the risk of a serious infection
Other surgery to the inside of the uterus can also lead to Asherman’s syndrome, including:
- Myomectomy: an operation to remove one or several fibroids. These are relatively common non-cancerous growths that can cause cramps, bleeding and abdominal swelling.
- Caesarean section: this may be planned or performed in an emergency.
Asherman’s syndrome can also result from an infection in the uterus such as genital tuberculosis (a major cause in the developing world).
Why does a D&C cause Asherman’s syndrome?
Dilation and curettage involves dilating the cervix and inserting a curette, which is a small medical instrument used for scraping, into the cavity of the uterus. Physical scraping (curettage) is used to remove a sample of endometrium or fragments of placenta. Over-vigorous scraping can also remove the top layer of uterine lining tissue, known as the basal layer, particularly if the endometrium is infected or the D&C is extensive.
Once the basal layer is stripped away there are no glands left to regenerate the endometrial carpet during the next monthly cycle. The exposed tissue is left unprotected and adhesions tend to form with nearby tissue due to the normal healing process. This often occurs near to the cervix, where the damage caused by a D&C is the greatest, effectively sealing the entrance to the uterus.
What are the symptoms of Asherman’s syndrome?
- Scant or non-existent periods due to adhesions blocking the cervix.
- Mild or more severe cramping at the usual time of the period because the menstrual blood cannot escape.
- Development or worsening of endometriosis due to retrograde menstruation in which blood moves back through the fallopian tubes and into the peritoneal cavity.
- Difficulties conceiving even though tests show hormone levels are normal.
Few women are aware that a D&C or fibroid removal can lead to Asherman’s and the symptoms can easily be explained away. A woman who breastfeeds for several months would not expect her periods to restart and a woman with significant fibroids would expect menstrual bleeding to be much lighter after they had been removed. These assumptions are often reinforced by health professionals.
Infertility may occur but may not become apparent for months until a woman starts to think of her next pregnancy. In cases of Asherman’s syndrome where the cervical canal is completely obstructed, conception is unlikely as sperm cannot make it through the cervix even if the endometrium in the upper part of the cavity is normal. In vitro fertilisation (IVF) has little chance of success as a fertilised embryo cannot implant in the uterus if damage to the lining is extensive.
How common is Asherman’s syndrome?
Estimates of the proportion of D&C procedures that lead to Asherman’s syndrome vary widely however the incidence is likely to be in the region of 5%. Very few studies have looked at this, and those that have taken place have included only a small number of women, so it is difficult to be absolutely sure. It is also likely that many cases go undiagnosed. This is particularly true where a woman may have had two or three children already. To some extent the scanty periods do not cause concern, especially if she does not experience any pain.
Awareness of Asherman’s syndrome is low, both among women and among non-specialist health professionals and this can lead to missed cases and untreated infertility. GPs may only see two or three cases a year, and most Consultant gynaecologists also probably only make the diagnosis a handful of times each year. Only a few gynaecologists specialise in this condition, but they may see 2 or 3 cases a week as a result of tertiary referral from other specialists and self-referral through self-help websites.
Unfortunately, because there are only a few such specialists in the UK, women may spend several months or even years having tests that conclude their infertility is ‘unexplained’. A delay in diagnosis can mean that treatment is more difficult as the adhesions and scar tissue that are typical of Asherman’s syndrome become thicker and more extensive over time.
How is Asherman’s syndrome diagnosed?
The adhesions that form inside the uterus are difficult to see on a standard two-dimensional ultrasound scan and can be easily missed by a non-specialist radiographer. Accurate diagnosis is done using a 3D ultrasound scan in combination with a hysterosalpingogram, (an x-ray of the uterus and fallopian tubes), followed by a hysteroscopy, which is also used to remove the adhesions.
Diagnostic imaging is best done simultaneously with treatment so that the surgeon can gain a better three-dimensional impression of the exact position of the affected areas of uterine lining. This 3D-road map cannot be gained by reading a radiologist’s report.
Treating Asherman’s syndrome
Treatment is best performed under general anaesthetic. An initial hysterosalpingogram is performed using contrast medium that shows up on X-rays; this fluid is introduced into the cervix. X-rays are then taken to follow the movement of the liquid through the uterus and fallopian tubes. If the cervix has an open channel, the fluid will find a way through, providing useful information to the gynaecologist. If the cavity of the uterus is still open, and the fallopian tubes are clear, the contrast medium will then appear in the abdominal cavity.
The path that the contrast medium takes is used to plot the path for the hysteroscope. This is a very fine tube, around 2mm in diameter, which contains light and a tiny camera. It is gently introduced through the cervix without dilation if possible. A tiny pair of scissors introduced through a slim side channel in the hysteroscope is used to peel away any adhesions. This is a slow and painstaking process and the surgeon works to clear away as many of the adhesions as possible without causing further damage, leaving the cervix and cavity of the uterus clear.
Recovery following treatment for Asherman’s syndrome
Although women undergoing treatment for Asherman’s syndrome have a general anaesthetic, most are allowed home later the same day. Some women experience some cramping and bleeding but recover quite quickly. The surgeon usually puts an intra-uterine contraceptive device (IUCD) in place just after the hysteroscopy to prevent new adhesions forming, and prescribes a high dose oestrogen to take for the next 28 days. This can be as high as 8mg of oestrogen per day and this encourages the endometrium to regenerate. Progesterone is introduced from days 15-28.
When hormone treatment is stopped, if the adhesions have been removed successfully, the woman should have a reasonably normal period. No formal studies have been done yet on outcomes, but a specialist gynaecologist seeing cases regularly expects around 90% of treated women to report a subsequent positive pregnancy test.
Outcome of treatment for Asherman’s syndrome
Every case is assessed individually. The outcome is usually better with less severe cases that are diagnosed with little delay. Complete absence of periods does not necessarily predict a poor outcome as this can be caused by an isolated adhesion within the cervix and the majority of the cavity above this obstruction can be normal. The worst outcome occurs in women who have had complete destruction of the endometrial cavity. For these women the only hope of having a family may lie with IVF surrogacy.