Asherman’s Syndrome (AS), also known as intrauterine adhesions (IUA) or synechiae, is a uterine condition characterized by the formation of scar tissue within the uterine cavity, often leading to menstrual irregularities and fertility challenges. Dilation and Curettage (D&C) is a common gynecological procedure performed to diagnose abnormal bleeding or to clear the uterus after a miscarriage or delivery. While D&C is generally safe, it is the most frequent cause of AS, and understanding the specific risks based on the context of the procedure is important.
The Pathology of Endometrial Scarring
Asherman’s Syndrome is fundamentally a problem of abnormal wound healing inside the uterus. The inner lining of the uterus, the endometrium, consists of two layers: a functional layer that sheds monthly and a basal layer underneath that is responsible for regenerating the functional tissue. Trauma to the uterus, such as from a surgical procedure like a D&C, can damage this crucial basal layer.
When the basal layer is injured, the normal regeneration process is disrupted, and the exposed areas on the opposing walls of the uterus stick together. This creates bands of fibrous scar tissue, or adhesions, which partially or completely obliterate the uterine cavity. The severity of the syndrome depends on the extent of this scarring, ranging from thin, filmy bands to dense, thick tissue that fuses the uterine walls together. This damage prevents the healthy regrowth of the functional endometrium, leading to the clinical symptoms of the syndrome.
Statistical Risk Following D&C
The risk of developing Asherman’s Syndrome following a D&C varies significantly based on the reason for the procedure and the patient’s reproductive status. Over 90% of AS cases are linked to D&C procedures performed on a uterus that is or was recently pregnant. A recently pregnant uterus is highly vulnerable to trauma, making it more susceptible to developing scar tissue.
The lowest incidence is seen after a diagnostic D&C, which is performed for non-pregnancy-related reasons like evaluating abnormal bleeding. The risk increases substantially when the D&C is performed to remove retained products of conception after a pregnancy loss.
Specific risk rates vary widely depending on the context:
- Following a first-trimester termination of pregnancy, the incidence is reported to be up to 13%.
- Following a late spontaneous abortion, the incidence can be as high as 30%.
- The highest risk (25% to 40%) is associated with a D&C performed after an incomplete miscarriage, especially if infection is present, or for retained placental tissue following a delivery.
The risk is compounded by factors like having multiple D&C procedures or a delay in the procedure after a pregnancy event.
Key Indicators of Asherman’s Syndrome
Asherman’s Syndrome primarily manifests through changes in the normal menstrual cycle following a uterine procedure. The most common indicator is a reduction in menstrual flow (hypomenorrhea) or the complete absence of periods (amenorrhea). These changes occur because the adhesions reduce the amount of functional endometrial tissue that can grow and shed each month.
Individuals may experience severe menstrual cramping or pelvic pain when their period should occur, even if little or no bleeding is present. This is caused by the obstruction of menstrual blood flow trapped within the uterine cavity by the scar tissue. The syndrome is often associated with reproductive issues, such as difficulty conceiving or recurrent pregnancy loss. Any noticeable change in a menstrual pattern after a D&C should prompt an investigation.
Confirmation and Treatment Options
If Asherman’s Syndrome is suspected based on symptoms and medical history, initial screening may involve imaging techniques like transvaginal ultrasound or sonohysterography. Sonohysterography involves injecting saline into the uterus to expand the cavity, allowing for a clearer view of the uterine walls to identify potential adhesions.
The definitive method for both confirming the diagnosis and determining the extent of the scarring is hysteroscopy. Hysteroscopy involves inserting a thin, lighted telescope through the cervix into the uterus, allowing a physician to directly visualize the adhesions.
This procedure is also the primary treatment, known as hysteroscopic adhesiolysis. During this surgery, fine instruments are used to carefully cut and remove the scar tissue, aiming to restore the natural size and shape of the uterine cavity.
Post-operative care is crucial to prevent the raw, newly separated uterine walls from scarring together again. This often involves placing a temporary physical barrier, such as a small balloon or a specialized intrauterine device, inside the uterus for several days. Additionally, high-dose estrogen therapy, followed by progesterone, is typically prescribed to stimulate the healthy regrowth of the endometrial lining.