Endometrial fibrosis is a condition involving the formation of scar tissue within the uterus, specifically affecting the endometrium, the organ’s inner lining. This scarring reduces the functional tissue necessary for a normal menstrual cycle or for supporting a pregnancy. The development of fibrosis indicates a significant disruption to the endometrium’s regenerative capacity. This issue primarily impacts reproductive health, often leading to challenges with menstruation and fertility.
Defining Endometrial Fibrosis
Endometrial fibrosis is the pathological replacement of normal, highly regenerative endometrial tissue with dense, non-functional fibrous connective tissue, primarily composed of excess collagen fibers deposited by myofibroblasts. The endometrium has two layers: the functional layer, which sheds monthly during menstruation, and the basal layer, which regenerates the functional layer. Fibrosis occurs when damage extends deep enough to injure the basal layer, impairing its ability to heal normally.
When this scarring is extensive, it leads to the formation of bands or sheets of scar tissue that connect the opposing walls of the uterus, a condition known as intrauterine adhesions (IUAs). Severe IUAs are commonly referred to as Asherman’s Syndrome. The severity depends on the extent of the synechiae—fibrous bands that partially or completely obliterate the uterine cavity. Scarring ranges from thin, filmy adhesions to dense, thick scar tissue that completely fuses the uterine walls.
Common Triggers and Risk Factors
The formation of scar tissue in the endometrium is typically an acquired condition resulting from trauma to the uterine lining. The most frequent cause is a surgical procedure called dilation and curettage (D&C), particularly when performed after a miscarriage or childbirth. During a D&C, a sharp instrument is used to scrape the uterine walls, and if this action is performed aggressively or repeatedly, it can inadvertently damage the underlying basal layer of the endometrium.
The risk of developing this condition is significantly higher when the uterus is in a pregnant or postpartum state, as the uterine lining is softer and more vulnerable to deep trauma. Surgical removal of uterine fibroids, known as myomectomy, especially when the fibroids penetrate the endometrial cavity, also carries a risk of inducing scarring. Other less common factors include infections like severe pelvic inflammatory disease (PID) or endometritis, which cause intense inflammation that can damage the endometrial stem cell niche.
Another potential cause is uterine artery embolization (UAE), a procedure used to treat uterine fibroids by blocking the blood supply. The resulting lack of oxygen, or ischemia, can cause parts of the endometrium to die and be replaced by fibrotic tissue. Chronic inflammation from infections, such as genital tuberculosis, though rare in Western countries, is a recognized cause of severe, widespread endometrial fibrosis globally.
Recognizing Symptoms and Diagnostic Procedures
One of the most common symptoms is secondary amenorrhea, the complete absence of menstrual bleeding, or hypomenorrhea, which is a significantly reduced or very light flow. This occurs because the scar tissue has replaced the functional endometrium that normally thickens and sheds each month. In some cases, patients may experience cyclic pelvic pain, which happens when adhesions block the cervical canal, trapping menstrual blood inside the uterus, a condition called hematometra.
Endometrial fibrosis is also a major cause of infertility and recurrent miscarriage. The presence of scar tissue physically distorts the uterine cavity, preventing the successful implantation of an embryo. Furthermore, the fibrotic tissue has poor blood supply, which creates a hostile environment that cannot sustain a developing pregnancy, often leading to early loss.
Diagnosis requires specialized imaging, as a standard transvaginal ultrasound may only show a thin or irregular uterine lining, which is often inconclusive. Hysterosalpingography (HSG), an X-ray procedure using contrast dye, is used as a screening tool to visualize the cavity’s outline, revealing “filling defects” where the scar tissue has reduced the uterine volume. The gold standard for both diagnosis and grading is hysteroscopy, which involves inserting a thin, lighted camera into the uterus for direct visualization of the location, extent, and type of adhesions.
Treatment Strategies for Endometrial Fibrosis
The primary treatment for endometrial fibrosis is surgical hysteroscopy, specifically adhesiolysis, aimed at removing scar tissue and restoring the uterine cavity’s normal shape. This surgery is performed under direct visualization, allowing precise dissection of the adhesions. To minimize further trauma to the fragile basal layer, sharp instruments, such as micro-scissors, are favored over energy-based tools like electrocautery, preventing thermal damage that could lead to new scar formation.
Preventing the reformation of adhesions after surgery is a primary focus. To keep the healing uterine walls from touching, a physical barrier is often placed inside the cavity for several days. This barrier can be an intrauterine splint or a pediatric Foley catheter balloon. Alternatively, anti-adhesive gels, such as hyaluronic acid, are injected to coat the surgical site and provide temporary physical separation.
Simultaneously, high-dose hormonal therapy is initiated to stimulate rapid regeneration of the endometrium. This involves prescribing high-dose oral estrogen (e.g., estradiol) for several weeks, followed by progestin to induce a withdrawal bleed. Estrogen encourages healthy endometrial tissue to grow and cover the newly separated areas before scarring can recur. The prognosis for achieving a successful pregnancy depends on the initial severity of the adhesions, but many women have a favorable outlook after adequate management.