What Is Proliferative Endometrium?
"Disordered proliferative endometrium" is a somewhat vague term that generally indicates the unusual growth of endometrial cells. The term can refer to a form of simple endometrial hyperplasia — or the abnormal thickening of the endometrial lining — but it can indicate a more serious problem in some cases. Here is some information about the potential causes of disordered proliferative endometrium and what that might mean for your patients.
Proliferative Endometrium Basics
Proliferative endometrium is part of the female reproductive process. The main purpose of the endometrium is to provide an attachment site and a source of nourishment to an early embryo. At the start of the menstrual cycle, the ovaries secrete the estrogen hormone, triggering the endometrium to enter a proliferative phase, during which it expands about six millimeters before plateauing around day nine or 10 of the cycle. At that time, the ovaries begin releasing progesterone in preparation for pregnancy. If conception doesn't occur, hormone levels drop, and the endometrium begins to shed.
While this cycle is common knowledge to gynecologists, the causes of disordered proliferative endometrium are less clear. Researchers are uncovering various potential influences on the proliferative phase of endometrial growth, which may help explain the process.
Proliferative Endometrial Conditions
A disordered proliferative endometrium can be associated with several different conditions, which range from benign to more serious. These include:
- Endometrial hyperplasia, a thickening of the endometrium that, according to The American College of Obstetricians and Gynecologists, typically occurs during perimenopause, after menopause or in response to high doses of estrogen or medications that act like estrogen. Obesity is also a risk factor for endometrial hyperplasia.
- Uterine polyps, which can occur in women of all ages but are most common after menopause.
- Endometrial cancer.
Symptoms include heavy bleeding, painful periods, bleeding between periods or after menopause (proliferative endometrium after menopause), irregular menstrual cycles and difficulty getting pregnant (disordered proliferative endometrium pregnancy). The causes of this disordered condition are varied, and ultrasound can be particularly useful when evaluating a patient with presenting symptoms. Ultrasound can be used to measure the thickness of the endometrium, for example, and 3D and saline infusion ultrasounds provide the imaging quality necessary for assessing endometrial abnormalities, such as polyps.
A Genetic Link?
Recent research from the Reproductive Sciences journal suggests that, along with hormonal influences, genes may also play a role in the development of disordered proliferative endometrium. This research discusses evidence of a higher expression of the genes related to proliferation, inflammation and immune response — including the genes TGFB2 and ligand 18 — during the early endometrial proliferative phase. Changes in genes associated with implantation, as well as with cell growth, appear to occur during the mid-proliferative phase. There is also a higher expression of genes related to the function sex hormone receptors at this time, which may help explain why endometrial proliferation typically stops even when high levels of estrogen are still circulating. Other research has found a link between a type of gene expression called telomeric repeat-containing RNA, endometrial conditions and cancer.
While there's still much we don't yet know about the role of genes in this complex process of proliferative endometrial conditions, such findings suggest that changes in gene regulation — not just changes in estrogen levels — are critical for endometrial growth. Stay tuned for more discoveries in this intriguing area of research.
