Asherman's Syndrome (Intrauterine Adhesions)

Table of Contents

  1. Overview
  2. Causes and Risk Factors
  3. Pathophysiology
  4. Clinical Presentation
  5. Diagnosis and Classification
  6. Hysteroscopic Treatment
  7. Post-Operative Adhesion Prevention
  8. Fertility and Pregnancy Outcomes
  9. Emerging Therapies
  10. Psychological Impact
  11. Key Research Papers
  12. Featured Videos

Overview

Asherman's syndrome — also called intrauterine adhesions (IUAs) or intrauterine synechiae — is a condition in which fibrotic scar tissue forms inside the uterine cavity, binding the walls together and destroying functional endometrium. The disease ranges from thin, filmy adhesions that partly bridge the cavity to dense, fibromuscular or connective-tissue bands that obliterate it entirely.

The condition was named after the Israeli gynecologist Joseph Asherman, who described it in 1948 after observing amenorrhea following uterine trauma. Its defining feature is damage to the basal layer of the endometrium — the regenerative stem-cell reservoir — leaving the cavity lined with scar rather than functional mucosa. Because the basal layer cannot regenerate after deep injury, even minimal surface damage to this layer can produce lasting adhesions.

Asherman's syndrome is almost always iatrogenic: caused by a medical or surgical procedure, most often a uterine curettage (D&C) performed after a pregnancy. It is the leading cause of secondary amenorrhea and infertility due to uterine factor worldwide. With careful hysteroscopic surgery and post-operative management, many patients can recover normal uterine function — but outcomes depend heavily on adhesion severity and underlying endometrial reserve.

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Causes and Risk Factors

The overwhelming majority of Asherman's syndrome cases follow damage to the pregnant or recently pregnant uterus. The gravid uterus is uniquely vulnerable because its decidualized endometrium is highly adherent and the basal layer lies close to the surface, making traumatic curettage more likely to denude it.

Dilation and Curettage (D&C) — The Most Common Cause

Sharp or suction curettage of the uterine cavity after a pregnancy event accounts for the majority of cases globally. The highest-risk scenarios include:

Other Uterine Surgeries

Genital Tuberculosis

In developing countries — particularly South Asia, sub-Saharan Africa, and parts of the Middle East — genital tuberculosis (TB endometritis) is the leading cause of severe Asherman's syndrome. Mycobacterium tuberculosis spreads hematogenously to the fallopian tubes and then descends to the endometrium, producing granulomatous inflammation followed by fibrotic scarring. Asherman's from TB is frequently the most severe form — complete obliteration of the cavity — and the poorest prognosis for fertility restoration. Any patient from an endemic region presenting with Asherman's should be screened with a tuberculin skin test (PPD) or IGRA (interferon-gamma release assay).

Infection

Severe uterine infections — whether from PID, postabortal sepsis, or postpartum endometritis — can independently cause adhesion formation even without preceding curettage. Infection amplifies the inflammatory-fibrotic response and makes curettage-related adhesions far more severe.

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Pathophysiology

Normal endometrial regeneration depends on an intact basalis layer — the deepest zone of the endometrium that is not shed during menstruation. It contains stromal stem cells and glandular progenitors that reconstitute the functionalis (the hormonally responsive upper layer) each cycle. When the basalis is injured, this regenerative capacity is lost in the affected area.

Instead of regeneration, the denuded myometrium responds with fibroblast proliferation and collagen deposition. Adjacent denuded walls fuse during healing, forming adhesions that bridge the cavity. The adhesion type determines clinical severity:

Critically, adhesion lysis does not automatically restore endometrial function. Even after the mechanical obstruction is removed, the underlying basalis may be permanently depleted — leading to thin, non-receptive endometrium (endometrial thickness <7 mm on ultrasound) that cannot support implantation regardless of cavity shape. This is why cavity restoration and endometrial regeneration are separate challenges, and why outcomes in severe disease remain poor even with technically successful surgery.

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Clinical Presentation

The hallmark of Asherman's syndrome is a change in menstrual pattern after a uterine procedure. The most important diagnostic clue is the temporal relationship: periods that were previously normal become scanty, painful, or absent after a D&C or other uterine surgery.

Menstrual Abnormalities

Cyclic Pelvic Pain Without Bleeding (Cryptomenorrhea)

When adhesions seal the cervical os or lower cavity but the upper uterus still produces menstrual fluid, blood accumulates behind the obstruction. The patient experiences monthly cramping at the expected time of menstruation without any external bleeding. This hematometra (blood pooling in the uterus) is an important diagnostic clue when it occurs cyclically after a uterine procedure. Severe hematometra causes severe pelvic pain and distension visible on ultrasound.

Infertility

Adhesions can cause infertility through several mechanisms: physical obstruction of the cavity prevents sperm ascent or embryo implantation; scarred endometrium lacks the receptivity needed for trophoblast invasion; and poor endometrial thickness (thin lining) prevents adequate decidualization. Women may present to fertility clinics without recognizing they have Asherman's, particularly if hypomenorrhea was subtle.

Recurrent Pregnancy Loss

Even partial adhesions that do not prevent implantation can cause recurrent miscarriage by restricting cavity space, impairing blood flow to developing placenta, or creating a hostile implantation environment. Asherman's should be part of the workup for recurrent pregnancy loss.

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Diagnosis and Classification

Asherman's syndrome requires direct visualization or imaging of the uterine cavity to diagnose. Hormone levels alone are insufficient — the defining feature is intrauterine pathology, not hormonal disruption.

Hysteroscopy (Gold Standard)

Operative hysteroscopy is simultaneously the definitive diagnostic and primary therapeutic tool. The hysteroscope — a thin camera inserted through the cervix — directly visualizes the adhesions, characterizes their type and extent, and allows immediate lysis. The American Fertility Society (AFS) classification and the European Society of Gynecological Endoscopy (ESGE) classification both grade adhesions by extent and type:

Saline Infusion Sonohysterography (SIS/SHG)

Sterile saline is instilled into the uterine cavity under transvaginal ultrasound guidance. Adhesions appear as filling defects or bands that persist within the fluid-distended cavity. SIS is less invasive than hysteroscopy and can be performed in the office. It reliably detects moderate to severe adhesions but may miss thin filmy adhesions in a small cavity.

Hysterosalpingography (HSG)

Radiographic contrast is injected into the cavity under fluoroscopy. Adhesions produce irregular filling defects. HSG is often the first-line test because it simultaneously evaluates tubal patency in the infertility workup. A normal HSG essentially excludes significant adhesions.

MRI

Reserved for complex or severe cases to characterize the fibromuscular versus connective tissue nature of adhesions and assess the remaining endometrial stripe. MRI helps predict prognosis for endometrial regeneration after adhesiolysis.

3D Ultrasound

Three-dimensional transvaginal ultrasound is emerging as a useful, non-invasive tool for characterizing cavity architecture, particularly to distinguish septa from adhesions and evaluate the depth of obliteration.

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Hysteroscopic Treatment

The primary treatment of Asherman's syndrome is hysteroscopic adhesiolysis — surgical division of adhesions under direct visualization. The goal is restoration of the normal uterine cavity shape and maximum endometrial surface area.

Surgical Approach

Adhesiolysis is performed with sharp scissors (cold scissors preferred for filmy adhesions to minimize thermal damage to adjacent endometrium), electrosurgical instruments, or laser. The surgeon systematically divides adhesions working from the cervical os toward the fundus, restoring the tubal ostia (tubal openings) to visibility. For severe obliteration, ultrasound or laparoscopic guidance may be used concurrently to prevent uterine perforation.

The number of procedures required depends on severity. Mild Asherman's typically requires one hysteroscopy. Moderate disease may need two procedures 2–3 months apart. Severe disease (dense connective tissue adhesions, complete obliteration) may require three or more staged procedures, and complete restoration of a normal functional cavity may not be achievable.

Success Rates by Severity

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Post-Operative Adhesion Prevention

The major challenge after adhesiolysis is preventing the walls from re-fusing during healing. Re-adhesion rates without post-operative treatment are high, particularly for moderate and severe disease. Multiple strategies are used in combination.

Mechanical Spacers

Estrogen Therapy for Endometrial Regeneration

High-dose exogenous estrogen is the most widely used adjunct to surgery. The rationale: estrogen drives endometrial proliferation, helping the remaining functional basalis cells regenerate and resurface the denuded cavity before fibroblasts can form new adhesions. A typical regimen includes conjugated estrogens (e.g., Premarin 2.5–5 mg/day) or estradiol for 30–60 days, with progestins added in the final 7–10 days to induce withdrawal bleeding and confirm endometrial response. Evidence is largely observational, but the regimen is near-universal in clinical practice for moderate and severe disease.

Hyaluronic Acid Gel

Anti-adhesion gels (e.g., Hyalobarrier) instilled into the cavity after adhesiolysis create a temporary physical barrier between raw surfaces. Meta-analyses suggest a modest reduction in re-adhesion rates with hyaluronic acid gel compared to no gel, though evidence remains heterogeneous.

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Fertility and Pregnancy Outcomes

Restoring the uterine cavity does not guarantee successful pregnancy. Outcomes depend on adhesion severity, the patient's age, the integrity of the underlying endometrium, and ovarian reserve.

Pregnancy Rates After Treatment

Obstetric Risks After Asherman's

Even women who achieve pregnancy after Asherman's treatment face elevated obstetric risks from residual uterine scarring:

Women who have had Asherman's syndrome and become pregnant require close obstetric monitoring, including early placental localization by ultrasound and careful delivery planning at a center equipped to manage placenta accreta.

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Emerging Therapies

The challenge of poor endometrial regeneration in severe Asherman's — even after perfect adhesiolysis — has driven active research into therapies that can stimulate endometrial stem cells or replace lost endometrial tissue.

Platelet-Rich Plasma (PRP)

Autologous PRP — concentrated platelets from the patient's own blood, rich in growth factors (VEGF, PDGF, EGF, TGF-β) — is infused directly into the uterine cavity or injected subendometrially. The growth factors aim to stimulate angiogenesis and endometrial regeneration. Multiple small trials and case series report improvements in endometrial thickness and pregnancy rates. A 2021 randomized trial found intrauterine PRP significantly improved endometrial thickness and clinical pregnancy rates in women with refractory thin endometrium post-Asherman's. PRP is now offered at many fertility centers for women with inadequate endometrial response after adhesiolysis.

Bone Marrow-Derived Stem Cells

Autologous infusion of CD133+ bone marrow stem cells via uterine artery catheterization has been explored in small series. The hypothesis is that marrow-derived progenitor cells home to the injured endometrium and differentiate into endometrial cells. Early results from teams in Spain, Israel, and China suggest increased endometrial thickness and occasional pregnancy in women with severe refractory disease. Larger controlled trials are underway but this remains experimental.

Regenerative Scaffolds

Biodegradable scaffolds seeded with endometrial stem cells or growth factors are in early laboratory and animal stages. The concept is to provide a structural template for endometrial regrowth in a completely obliterated cavity. Human applications are investigational.

Granulocyte Colony-Stimulating Factor (G-CSF)

Intrauterine instillation of G-CSF — a cytokine that recruits bone marrow progenitor cells and promotes angiogenesis — has shown improvements in endometrial thickness in several small trials. It is used off-label at some centers for thin endometrium unresponsive to estrogen therapy.

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Psychological Impact

Asherman's syndrome carries a disproportionate psychological burden because it typically strikes after what should have been a routine procedure — a D&C after a miscarriage or pregnancy complication — and its consequences (infertility, menstrual changes) emerge gradually over the following months, often without the patient being told that the D&C could have caused harm.

Many women with Asherman's describe medical gaslighting: being told that scanty periods after a D&C are "normal" or "the uterus settling," and not receiving a diagnosis for months or years. This delay is compounded by the condition's relative obscurity — many generalist physicians have limited familiarity with IUAs.

Common psychological sequelae include:

Peer support communities (the Asherman's Syndrome Sisterhood, the International Asherman's Association) have been critical in helping patients navigate diagnosis, find experienced surgeons, and process the emotional consequences of a condition that is poorly recognized by the general medical community. Psychological support and fertility counseling should be integrated into the treatment plan.

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Key Research Papers

The following peer-reviewed publications underpin current understanding and management of Asherman's syndrome.

  1. Asherman JG. Amenorrhoea traumatica (atretica). Journal of Obstetrics and Gynaecology of the British Empire. 1948;55(1):23–30. PMID 18903252
  2. March CM. Management of Asherman's syndrome. Reproductive BioMedicine Online. 2011;23(1):63–76. PMID 21549641
  3. Yu D, Wong YM, Cheong Y, Xia E, Li TC. Asherman syndrome — one century later. Fertility and Sterility. 2008;89(4):759–779. PMID 18406834
  4. Valle RF, Ekele B. Hysteroscopic treatment of intrauterine adhesions. Seminars in Reproductive Medicine. 2017;35(1):68–74. PMID 28196393
  5. Salma U, Xue M, Sheikh Ali Talpur MH, Haider S. Efficacy of intrauterine device or intrauterine balloon after operative hysteroscopy in prevention of intrauterine adhesions. BioMed Research International. 2014;2014:589269. PMID 25243140
  6. Chen L, Zhang H, Wang Q, et al. Reproductive outcomes in patients with intrauterine adhesions following hysteroscopic adhesiolysis: experience from the largest women's hospital in China. Journal of Minimally Invasive Gynecology. 2017;24(2):299–304. PMID 27956198
  7. Deans R, Abbott J. Review of intrauterine adhesions. Journal of Minimally Invasive Gynecology. 2010;17(5):555–569. PMID 20656566
  8. Johary J, Xue M, Zhu X, Xu D, Velu PP. Efficacy of estrogen therapy in patients with intrauterine adhesions: systematic review. Journal of Minimally Invasive Gynecology. 2014;21(1):44–54. PMID 24200937
  9. Chang Y, Tsai EM, Long CY, Lee CL, Kay N. Resectoscopic treatment combined with sonohysterographic evaluation of women with intrauterine adhesions. American Journal of Obstetrics and Gynecology. 2000;182(3):510–515. PMID 10739499
  10. Kou L, Liu X, Ding X, et al. Platelet-rich plasma improves the prognosis of patients with intrauterine adhesion by promoting the expression of TGF-β3 and decorin. Biomedicine & Pharmacotherapy. 2020;131:110718. PMID 32916531
  11. Cao M, Liu Y, Hou Y, et al. Granulocyte colony stimulating factor administration in intrauterine adhesion patients following transcervical resection of adhesion. Experimental and Therapeutic Medicine. 2016;12(4):2942–2948. PMID 27882109
  12. AAGL Elevating Gynecologic Surgery. AAGL practice report: practice guidelines for management of intrauterine synechiae. Journal of Minimally Invasive Gynecology. 2010;17(1):1–7. PMID 20129334

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Connections

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