14.1 Introduction

The presence of intrauterine adhesions and the association with secondary amenorrhea were first described by Dr. Fritsh in 1894. In 1948, Dr. Joseph G. Asherman published a series of papers describing the etiology, symptoms, imaging findings, and fertility outcomes, and the condition has been known as Asherman’s syndrome (AS) since. Asherman’s syndrome was primarily described as an outcome of trauma to the basal layer of the endometrium, with subsequent formation of fibrotic adhesions leading to either partial or complete obstruction of the cervical canal or uterine cavity resulting in menstrual abnormalities, infertility, or recurrent pregnancy loss [1]. The initial definition of AS included confirmed IUAs with clinical features of amenorrhea, infertility, or recurrent pregnancy loss; however, today the presence of IUAs regardless of additional clinical features is often referred to as AS. For many, the terminologies Asherman’s syndrome (AS), intrauterine adhesions (IUA), and intrauterine synechiae (IUS) are interchangeable.

The exact prevalence of AS is difficult to identify as a large proportion of patients have no symptoms. The last worldwide investigation found that the highest prevalence of AS has been found in Israel, Greece, and South America [2]. AS was initially described to occur following trauma to a gravid uterus. Curettage in the postpartum period, following a spontaneous abortion or during an elective termination of pregnancy, or following a cesarean section have all been implicated to lead to IUAs. While trauma to the gravid uterus remains the most important risk factor for the development of IUAs, trauma to a nongravid uterus, infections, uterine anomalies, and genetic predispositions have also been linked to the development of IUAs resulting in potential AS.

The presence of IUAs can vary dramatically from patient to patient. There are numerous classifications of IUAs that exist, and all require the use of hysteroscopy to determine the extent and characteristics of the adhesions. A very commonly used classification system was proposed by the American Fertility Society which classifies the severity of the disease in three stages as follows [3]:

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Mild disease: few filmy adhesions involving less than a third of the uterine cavity with normal menses or hypomenorrhea

Moderate disease: filmy and dense adhesions, the involvement of one-third to two-thirds of cavity and hypomenorrhea

Severe disease: dense adhesions involving more than two-thirds of the cavity with amenorrhea

Treatment of IUAs depends on the associated clinical manifestations. IUAs are not life threatening, and in the asymptomatic patient should be treated with expectant management. Surgical intervention is only indicated when patients present with signs or symptoms of pain infertility, recurrent pregnancy loss, or menstrual abnormalities including hematometra. Multiple surgical interventions have been described for the treatment of IUAs; however, hysteroscopic adhesiolysis remains the gold standard for surgical management [4]. Hysteroscopic adhesiolysis has been proven to be a very safe procedure and provides direct visualization of adhesions to increase surgical precision [5]. In cases of mild disease with thin filmy adhesions, simply distending the uterus with fluid media is enough to break the adhesions and restore normal anatomy. If more disease is encountered, adhesiolysis can be performed with hysteroscopic scissors, biopsy forceps, and monopolar or bipolar electrocautery.

14.1.1 Complications Following Adhesiolysis

Complications can be divided into intraoperative complications, and postoperative complications. As with all operative hysteroscopy, the two major intraoperative complications encountered are bleeding and perforation. The most common intraoperative complication is hemorrhage, which has been reported in 6–27% of cases [1]. Injury to myometrial blood vessels may obstruct a surgeon’s view and enable for a more rapid absorption of the distention media possibly leading to major electrolyte disturbances. Uterine perforation is the second most common intraoperative complication and is seen in 2–5% of cases but has been reported in up to 9% of patients where severe IUAs were encountered. Table 14.1 includes documented complications following hysteroscopy adhesiolysis.

Table 14.1 Complications of hysteroscopic adhesiolysis for Asherman’s syndrome
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Surgical success at the time of surgery is typically believed to be achieved with restoration of a normal-appearing uterine cavity, which is accomplished in 57–98% of cases [6]. Despite removal of all adhesions, and restoration of a normal uterine cavity, adhesiolysis is associated with a high rate of IUA re-formation. The rate of re-formation of adhesions is high and is seen in 3.1–23.5% of cases, and has been reported in 20–62% of severe cases (Table 14.2). Numerous studies have investigated methods to decrease the re-formation of intrauterine adhesions. Table 14.3 reports different studies investigating IUA re-formation. At this time, no consensus protocol exists to prevent the recurrence of IUAs. Patients with severe disease should be counseled at the time of initial surgery for need for possible repeat surgery, as approximately 1/3 required a repeat procedure due to IUA re-formation [7].

Table 14.2 Outcome of hysteroscopic adhesiolysis for Asherman’s syndrome: restoration of menstruation in women presenting with amenorrhea or hypomenorrhea
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Table 14.3 Reports comparing various modalities to reduce re-formation of adhesion postresection
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14.1.2 Fertility Potential Following Adhesiolysis

Secondary infertility as the initial presenting symptom has been reported in up to 45% of patients, and the pursuit of fertility is the most common indication for hysteroscopic adhesiolysis [8]. Implantation issues have been hypothesized in patients with IUAs, and hysteroscopic adhesiolysis has been shown to improve endometrial thickness and endometrial receptivity [9]. Numerous studies have been performed documenting fertility outcomes following adhesiolysis, with pregnancy rates ranging from 10.5% to 100% [10]. Guo et al. performed a meta-analysis which included 54 studies, and found an overall pregnancy rate for all subjects of 50.7% following adhesiolysis, Table 14.4. When looking at pregnancy rates before and after surgery, one study found a pregnancy rate of 65.5% after adhesiolysis, compared to only 18% preoperatively [5]. That same study found a live birth rate of 36% after adhesiolysis, compared to only 14.7% preoperatively. Most patients attempting to conceive are able to achieve a pregnancy within 1 year postoperatively, and up to 97.2% can conceive within 24 months [11, 12].

Table 14.4 Pregnancy rate and live birth rate following adhesiolysis
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The degree of preoperative adhesions has been well documented to negatively impact postoperative fertility rates. Severe adhesions are more difficult than mild to restore normal uterine anatomy, and often require multiple procedures to achieve restoration of anatomy. Mild, moderate, and severe adhesions have been associated with conception rates of 64.7–69.1%, 53.6–61.3%, and 32.5–44.3%, respectively; see Fig. 14.1 [1, 10]. Two factors are implicated to effect conception when evaluating for the degree of preoperative adhesions: return to normal menstruation, and re-formation of adhesions. Patients with severe adhesions are more likely to have re-formation of IUAs, and are also less likely to have return of normal menstruation compared to patients with moderate or mild IUAs [1].

Fig. 14.1
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Pregnancy rate after hysteroscopic adhesiolysis. Adapted from Guo et al. [10]

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Hysteroscopic adhesiolysis helps increase both pregnancy and live birth rates, and while this is the goal for a large majority of patients undergoing adhesiolysis, patients need to be counseled on future pregnancy complications. Pregnancies that follow adhesiolysis have been associated with a number of adverse pregnancy complications; see Table 14.5. Compared to the general population, pregnancy after adhesiolysis is associated with increased rates of early pregnancy loss, placental abnormalities, cervical insufficiency, preterm birth, and most significantly complications associated with placenta accreta syndrome. Damage to the endometrium and prior intrauterine surgery increase the risk for development of placenta accreta.

Table 14.5 Prevalence of various adverse pregnancy outcomes for women who conceived after surgical treatment of AS compared with the rates in the general population
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14.2 Conclusion

Hysteroscopic adhesiolysis for patients with IUAs has been proven to be a safe and effective surgical intervention. Intraoperative complications are rare, and restoration of a normal uterine cavity is achieved in most cases. Patients with severe IUAs have increased risk of intraoperative complications and are more likely to require more than one procedure to restore normal intrauterine anatomy. Re-formation of IUAs is the most common postoperative complication and is seen in 1/3 of those with severe disease. Adhesiolysis significantly improves conception rates, and most patients are able to conceive within 2 years. Severity of IUA disease is negatively correlated with conception rates, likely due to increased re-formation of IUAs. Patients treated for IUAs should be counseled on increased risks for subsequent pregnancies, specifically the increased risks for placenta accreta syndrome.

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Key Points

  1. 1.

    Hysteroscopic adhesiolysis for patients with IUAs has been proven to be a safe and effective surgical intervention.

  2. 2.

    Intraoperative complications are rare, and restoration of a normal uterine cavity is achieved in most cases.

  3. 3.

    Severe IUAs have increased risk of intraoperative complications and are more likely to require more than one procedure to restore normal intrauterine anatomy.

  4. 4.

    Re-formation of IUAs is the most common postoperative complication and is seen in 1/3 of those with severe disease.

  5. 5.

    Adhesiolysis significantly improves conception rates, and most patients are able to conceive within 2 years.

  6. 6.

    Severity of IUA disease is negatively correlated with conception rates, likely due to increased re-formation of IUAs.

  7. 7.

    IUA-treated women should be counseled about increased risks of obstetric complications including placenta accreta syndrome.