Thin endometrium is often more than a fertility barrier, it can be a warning sign of deeper uterine damage. Among the potential causes, Asherman syndrome stands out as one of the most underdiagnosed yet impactful conditions affecting women’s reproductive health. Accurate diagnosis is essential not only to restore fertility but to prevent repeated failed implantation attempts and emotional strain.
This article offers a science-based guide to understanding how to identify Asherman syndrome, especially when thin endometrium is one of the presenting signs.
What Is Asherman syndrome?
Asherman syndrome is an acquired uterine disorder characterized by the formation of intrauterine adhesions (IUAs), or scar tissue, that partially or completely obliterate the uterine cavity. Unlike thin endometrium caused by hormonal imbalance, Asherman syndrome is mechanical and often results from surgical trauma like dilation and curettage (D&C).
Why thin endometrium matters in diagnosis
In many cases, thin endometrium is one of the first measurable signs of uterine scarring. A persistent lining measuring under 6–7 mm across several menstrual cycles, especially in women with a history of uterine surgery, should prompt further investigation.
Hysteroscopy: The gold standard for diagnosis
Why it’s superior to ultrasound alone
While transvaginal ultrasound can suggest endometrial thinning or asymmetries, only hysteroscopy allows direct visualization of adhesions. This in-office procedure involves inserting a thin, lighted camera through the cervix into the uterus, offering real-time assessment and the possibility of immediate intervention.
Advantages:
- Visual confirmation of adhesions
- Ability to assess adhesion location and severity
- Immediate classification (mild, moderate, severe)
- Simultaneous adhesiolysis in some cases
Reference: American Society for Reproductive Medicine Guidelines recommend hysteroscopy as the preferred method for diagnosing intrauterine adhesions.
When and how to suspect Asherman syndrome
High-risk clinical profiles
If you identify with any of these scenarios, a hysteroscopic evaluation may be warranted:
- History of D&C, especially after miscarriage or retained placenta
- Repeated failed embryo transfers with no identifiable cause
- Amenorrhea or light periods after surgery
- Unexplained thin endometrium despite adequate estrogen
- Previous diagnosis of chronic endometritis
Complementary imaging: what role do ultrasound and MRI play?
Transvaginal ultrasound
Although not definitive, certain ultrasound features can raise suspicion:
- Thin endometrial lining (<6 mm mid-cycle)
- Poor triple-line pattern
- Irregular or asymmetric cavity contour
Saline infusion sonohysterography (SIS)
This method introduces sterile saline into the uterus during an ultrasound, improving visualization of the uterine walls and possible adhesions.
MRI
Rarely used as a first-line diagnostic tool, MRI may be considered in complex or inconclusive cases.
Confirmatory tools: hysterosalpingography (HSG)
An older technique, HSG involves injecting contrast dye into the uterus and fallopian tubes while taking X-rays. While less precise than hysteroscopy, it may show filling defects suggestive of adhesions.
Note: HSG has a false-negative rate of up to 50% for intrauterine adhesions and is not recommended as a sole diagnostic tool.
H2 The diagnostic process step-by-step
- Clinical suspicion: Based on history, symptoms, and failed IVF cycles
- Baseline ultrasound: Assess endometrial thickness and pattern
- Saline sonogram (optional): To improve visualization
- Hysteroscopy: Direct inspection and possible classification
- Biopsy (if indicated): To rule out chronic endometritis
Taking action: what to do if you suspect Asherman syndrome
- Track menstrual changes post-surgery
- Seek a specialist in reproductive medicine
- Request a diagnostic hysteroscopy
- Avoid repeated blind curettage procedures
- Explore regenerative therapies if scarring is confirmed
Thin endometrium is a signal, not a sentence
For many women, thin endometrium is more than a diagnosis, it’s a call to investigate deeper. When caused by Asherman syndrome, early and precise diagnosis can make the difference between repeated IVF failures and restored fertility. If you’re navigating reproductive challenges and suspect endometrial damage, trust your instincts, ask the right questions, and seek out expert evaluation.