Thin endometrium—typically defined as an endometrial lining measuring less than 7 mm during the late proliferative phase—can significantly hinder a woman’s ability to conceive. Unlike Asherman syndrome, which involves scar tissue (adhesions) inside the uterus, thin endometrium is primarily characterized by inadequate endometrial proliferation and vascularization
While these conditions can coexist, especially in women with histories of uterine surgery or trauma, they are distinct in etiology
and treatment. This article focuses on the specific high-risk indicators that predispose women to develop thin endometrium and how to differentiate it from Asherman syndrome.
What Is thin endometrium?
A distinct but critical factor in reproductive health
The endometrium is a dynamic tissue that must reach a certain thickness and receptivity state to support embryo implantation. When too thin, implantation often fails—even in well-executed IVF cycles. This condition can be the result of hormonal, iatrogenic, or vascular factors, and is not necessarily associated with intrauterine adhesions as in Asherman syndrome.
Not to be confused with Asherman syndrome
Asherman syndrome is an acquired uterine condition characterized by the presence of intrauterine adhesions, often after surgical procedures like curettage. While it can lead to a thin or non-functional endometrial lining, the underlying mechanism involves endometrial tissue fibrosis—not insufficient proliferation. The diagnostic and therapeutic approaches differ, making correct identification essential.
High-risk indicators for developing thin endometrium
Hormonal deficiency or imbalance
Low estrogen levels, whether due to premature ovarian insufficiency, hypothalamic amenorrhea, or chronic stress, impair the proliferation of endometrial tissue. This is one of the most common causes of thin endometrium in reproductive-age women.
Uterine procedures without adhesion formation
Procedures like dilation and curettage (D&C), hysteroscopy, or myomectomy may disrupt the basal layer of the endometrium, leading to suboptimal regeneration—even without forming adhesions. This represents a non-Asherman, iatrogenic pathway to thin endometrium.
Aging and reduced endometrial responsiveness
With age, the endometrial stem cell niche may diminish in function, particularly after 40. Even with adequate estrogen levels, the endometrial lining may fail to respond effectively, leading to thin or hypovascularized tissue.
Chronic endometrial inflammation
Conditions such as chronic endometritis or repeated infections can damage the endometrial architecture and impair its ability to thicken, despite hormonal stimulation.
Repeated IVF failures without structural abnormalities
Patients with adequate ovarian response but repeated implantation failures should be assessed for functional thin endometrium, even in the absence of anatomical lesions.
The emotional and clinical impact of thin endometrium
Women diagnosed with thin endometrium often feel invisible. Unlike fibroids or polyps, the issue is not easily seen, yet it is profoundly impactful. Failed implantation and early pregnancy loss take an emotional toll, especially when the underlying cause remains unidentified.
Recognizing thin endometrium as a standalone diagnosis—separate from Asherman syndrome—is critical to choosing the right intervention.
Regenerative therapies: a new path forward
One of the most promising approaches for thin endometrium is PAULA therapy, which uses autologous CD133+ stem cells to stimulate vascularization and tissue regeneration. This therapy does not rely on hormone replacement or mechanical separation like traditional Asherman treatments but instead addresses the fundamental lack of regenerative capacity in the endometrium.
Steps you can take if you suspect thin endometrium
- Request a transvaginal ultrasound during the mid-to-late follicular phase
- Discuss estrogen and progesterone levels with your reproductive endocrinologist
- Ask about endometrial blood flow or vascular index scoring in Doppler studies
- Explore non-hormonal regenerative options if hormone therapies have failed
We are currently identifying potential patients for our Phase III clinical trial with PAULA Cell Therapy that is currently in the design and regulatory review phase. If you want more information, just write us at inquires.