Asherman's syndrome (AS) is an acquired uterine condition that occurs when scar tissue (adhesions) forms inside the uterus and/or the cervix. It is characterized by variable scarring inside the uterine cavity, where in many cases the front and back walls of the uterus stick to one another. AS can be the cause of menstrual disturbances, infertility, and placental abnormalities. Although the first case of intrauterine adhesion was published in 1894 by Heinrich Fritsch, it was only after 54 years that a full description of Asherman syndrome was carried out by Joseph Asherman. Several other terms have been used to describe the condition and related conditions including: uterine/cervical atresia, traumatic uterine atrophy, sclerotic endometrium, and endometrial sclerosis. AS can develop even if the woman has not had any uterine surgeries, trauma, or pregnancies. While rare in North America and European countries, genital tuberculosis is a cause of Asherman's in other countries such as India.

History

The condition was first described in 1894 by Heinrich Fritsch (Fritsch, 1894) and further characterized by gynecologist Joseph Asherman (1889–1968) in 1948.

It is also known as Fritsch syndrome, or Fritsch-Asherman syndrome.

Signs and symptoms

It is often characterized by a decrease in flow and duration of bleeding (absence of menstrual bleeding, little menstrual bleeding, or infrequent menstrual bleeding) and infertility. Menstrual anomalies are often but not always correlated with severity: adhesions restricted to only the cervix or lower uterus may block menstruation. Pain during menstruation and ovulation is sometimes experienced and can be attributed to blockages.

It has been reported that 88% of AS cases occur after a D&C is performed on a recently pregnant uterus, following a missed or incomplete miscarriage, birth, or during an elective termination (abortion) to remove retained products of conception.

Causes

The cavity of the uterus is lined by the endometrium. This lining is composed of two layers, the functional layer (adjacent to the uterine cavity) which is shed during menstruation and an underlying basal layer (adjacent to the myometrium), which is necessary for regenerating the functional layer. Trauma to the basal layer, typically after a dilation and curettage (D&C) performed after a miscarriage, or delivery, or abortion, can lead to the development of intrauterine scars resulting in adhesions that can obliterate the cavity to varying degrees. In the extreme, the whole cavity can be scarred and occluded. Even with relatively few scars, the endometrium may fail to respond to estrogen.

Asherman's syndrome affects women of all races and ages equally, suggesting no underlying genetic predisposition for its development. AS can result from other pelvic surgeries including cesarean sections, removal of fibroid tumours (myomectomy) and from other causes such as IUDs, pelvic irradiation, schistosomiasis and genital tuberculosis. Chronic endometritis from genital tuberculosis is a significant cause of severe intrauterine adhesions (IUA) in the developing world, often resulting in total obliteration of the uterine cavity which is difficult to treat.

An artificial form of AS can be surgically induced by endometrial ablation in women with excessive uterine bleeding, in lieu of hysterectomy.

Diagnosis

thumb|Hysteroscopic view of intrauterine adhesions

thumb|[[Hysterosalpingography|HSG showing filling defects at the adhesion sites. Additionally, this uterus appears to be T-shaped.]]

The history of a pregnancy event followed by a D&C leading to secondary amenorrhea or hypomenorrhea is typical. Hysteroscopy is the gold standard for diagnosis. It was suggested as early as 1993 The advantage of misoprostol is that it can be used for evacuation not only following miscarriage, but also following birth for retained placenta or hemorrhaging.

Alternatively, D&C could be performed under ultrasound guidance rather than as a blind procedure. This would enable the surgeon to end scraping the lining when all retained tissue has been removed, avoiding injury.

Early monitoring during pregnancy to identify miscarriage can prevent the development of, or, as the case may be, the recurrence of AS, as the longer the period after fetal death following D&C, the more likely adhesions may be to occur.

Intrauterine adhesions also form after hysteroscopic surgery such as myomectomy, polypectomy or septum removal. Mechanical barriers such as Womed Leaf

Treatment

Fertility may sometimes be restored by the removal of adhesions, depending on the severity of the initial trauma and other individual patient factors. Operative hysteroscopy is used for visual inspection of the uterine cavity during adhesion dissection (adhesiolysis). However, hysteroscopy is yet to become a routine gynaecological procedure and only 15% of US gynecologists perform office hysteroscopy. Adhesion dissection can be technically difficult and must be performed with care to not create new scars and further exacerbate the condition. In more severe cases, adjunctive measures such as laparoscopy are used in conjunction with hysteroscopy as a protective measure against uterine perforation. Microscissors are usually used to cut adhesions. Electrocauterization is not recommended.

As IUA frequently reforms after surgery, techniques have been developed to prevent the recurrence of adhesions. Methods to prevent adhesion reformation include the use of mechanical barriers (Foley catheter, saline-filled balloon uterine stents), gel barriers (Seprafilm, Spraygel, autocrosslinked hyaluronic acid gel Hyalobarrier) and mechanical barrier film (Womed Leaf) to maintain opposing walls apart during healing, thereby preventing the reformation of adhesions. A common pharmacological method for preventing reformation of adhesions is sequential hormonal therapy with estrogen followed by a progestin to stimulate endometrial growth and prevent opposing walls from fusing. Furthermore, diagnostic severity and outcomes are assessed according to different criteria (e.g., menstrual pattern, adhesion reformation rate, conception rate, live birth rate). More comparable studies are needed in which reproductive outcomes can be analysed systematically. However, the latest randomized controlled trial, published in July 2024, demonstrated a clinically significant improvement in a group of patients with Asherman syndrome who received the Womed Leaf mechanical barrier film compared to a control group where no adhesion prevention tool was used.

Follow-up tests (HSG, hysteroscopy or SHG) are necessary to ensure that adhesions have not reformed. Further surgery may be necessary to restore a normal uterine cavity. According to a recent study among 61 patients, the overall rate of adhesion recurrence was 27.9%. In moderate and severe cases, it is up to 76%. If left untreated, the obstruction of menstrual flow resulting from adhesions can lead to endometriosis in some cases.

Patients who carry a pregnancy even after treatment of IUA may have an increased risk of having abnormal placentation including placenta accreta where the placenta invades the uterus more deeply, leading to complications in placental separation after delivery. Premature delivery, second-trimester pregnancy loss, and uterine rupture are other reported complications. They may also develop incompetent cervix where the cervix can no longer support the growing weight of the fetus, the pressure causes the placenta to rupture, and the mother goes into premature labour. Cerclage is a surgical stitch that helps support the cervix if needed.

Age is another factor contributing to fertility outcomes after treatment of AS. For women under 35 years of age treated for severe adhesions, pregnancy rates were 66.6% compared to 23.5% in women older than 35. up to 30.9% of D&Cs performed for missed miscarriages and 6.4% of D&Cs performed for incomplete miscarriages. In another study, 40% of patients who underwent repeated D&C for retained products of conception after missed miscarriage or retained placenta developed AS.

In the case of missed miscarriages, the time period between fetal demise and curettage may increase the likelihood of adhesion formation due to fibroblastic activity of the remaining tissue.

The risk of AS also increases with the number of procedures: one study estimated the risk to be 16% after one D&C and 32% after three or more D&Cs. However, a single curettage often underlies the condition.

In an attempts to estimate the prevalence of AS in the general population, it was found in 1.5% of women undergoing hysterosalpingography HSG, and between 5 and 39% of women with recurrent miscarriage.

After miscarriage, a review estimated the prevalence of AS to be approximately 20% (95% confidence interval: 13% to 28%).

References

  • Sophie Blake talks about being diagnosed with Asherman's syndrome.
  • (awareness, education, prevention)