Description

• Asherman syndrome (AS) is the term used to describe symptoms (i.e., amenorrhea or infertility) associated with intrauterine adhesions (IUAs) or development of scar tissue within the endometrium.
• The extent of IUAs can range from minimal disease causing thin, filmy adhesions from the anterior uterine wall to the posterior uterine wall to complete obliteration of the intrauterine cavity due to large thick adhesions comprised largely of dense connective tissue.
• The severity to which these adhesions cause symptoms of infertility or abnormal menses will dictate the level of disease.
• The manifestations of IUA include decrease in menstrual flow, infertility, recurrent miscarriage, placenta accreta, amenorrhea, and so forth, which significantly influence reproductive health.
• The leading risk factor for IUAs and AS is intrauterine trauma associated with a surgical instrumentation or manipulation.
• Treatment is indicated by the extent of disease and consists of lysis of adhesions and preventative measures.

Epidemiology

Incidence
As intrauterine adhesive disease is generally asymptomatic, true incidence and prevalence is difficult to measure.

Prevalence
Estimates of prevalence range from 1.5% as an incidental finding to 21.5% of women with history of postpartum uterine curettage (1).

Etiology and Pathophysiology

• The etiology of this disorder is trauma to the basalis layer of the endometrium (1).
• The basalis layer appears to be more susceptible to damage in the first 4 weeks postpartum or postabortal (1).
• The basalis layer of endometrium is damaged, causing inactive regeneration of endometrial cells and glands leading to poor endometrial repair signaling and defective angiogenesis (2).The absence of vascular regeneration causing interruption in the endometrium causes formation of fibrous scar and adhesion between anterior and posterior walls (2).
• Possible explanations for uterine susceptibility to IUA formation following pregnancy include the low estrogen state associated with the postpartum or postabortion time period, antagonistic effects from elevated prolactin levels associated with breastfeeding, or postpregnancy physiologic changes that make the basalis layer more susceptible to injury (3).
• Endometrial injury from procedures unrelated to pregnancy has also been implicated in the disease process, that is, myomectomy or curettage performed in the nonpregnant uterus.
• Infectious processes have also been found as a cause of adhesive disease within the endometrium. Although studies have shown conflicting evidence, genital tuberculosis is one of the main etiologic factors of this condition, whereas chronic endometritis has also been associated with IUA.
• After endometrial injury, impaired endometrial repair is thought to be the pathogenesis behind IUA (2).

Risk Factors

• Endometrial curettage up to 4 weeks postpartum
• Recurrent miscarriages and D&C procedures
• Congenital (septate uterus or bicornuate uterus) and acquired intrauterine abnormalities (polyps or fibroids) have been identified more frequently in woman with IUA (4).
• Women with more than one miscarriage generally have more IUAs compared with women with one miscarriage (4).
• Uterine compression sutures (e.g., B-Lynch suture) used to treat severe postpartum hemorrhage have been associated with the development of IUAs. In four retrospective reviews, IUAs were diagnosed in 19–27% of women who received uterine compression sutures to treat postpartum hemorrhage (5).

General Prevention

• Avoiding repeated intrauterine curettage for early pregnancy loss by opting for expectant and medical management especially in women with history of previous uterine instrumentation
• Other measures have been proposed, such as routine estrogen therapy, after uterine curettage and using hyaluronic acid as an adhesion barrier; however, no studies have demonstrated clinical benefit from these approaches.

Commonly Associated Conditions

• Associated with müllerian duct malformations, especially with septate uterus
• Patients with remaining areas of normally functioning endometrium may have increased risk of developing endometrial adenocarcinoma (1).
• Endometriosis from backflow of menstrual fluid