Endometriosis/Adenomyosis and Congenital Uterine Malformations: Correlation of ESHRE/ESGE classes to #ENZIAN compartments

For many women, the journey to understand their reproductive health begins with a question that feels simple but is often complex: why is the uterus shaped the way it is, and does that shape matter for their well-being? The uterus is a muscular organ where a pregnancy grows, but in some women, it develops with a different shape from the start. These are known as congenital uterine malformations. While the organ might look unusual on the inside or outside, it is not a disease in itself, but a variation in how the body formed. Alongside these structural differences, many women also struggle with endometriosis, a condition where tissue similar to the lining of the uterus grows in places it should not be, causing pain and other issues. Scientists have long wondered if the shape of the uterus influences where this tissue grows or how severe the condition becomes. The prevailing idea is that if the uterus does not contract normally or if menstrual flow is blocked, it might push tissue backward into the pelvis, where it can implant and grow. Understanding the link between a woman's unique uterine shape and the specific pattern of her endometriosis could change how doctors diagnose and treat her, moving from a one-size-fits-all approach to a plan tailored to her specific anatomy.

A team of researchers at the University of Rome Tor Vergata set out to map this connection with precision. They looked at 304 women, all of whom had been diagnosed with a congenital uterine malformation. Using a highly detailed three-dimensional ultrasound, a technique that creates a clear, three-dimensional picture of the pelvic organs, the doctors categorized each woman's uterus according to a standard international system. They then examined these same women for signs of endometriosis and adenomyosis, a related condition where uterine lining tissue grows into the muscle wall of the uterus. Instead of just noting whether endometriosis was present, the researchers used a comprehensive mapping system called the #Enzian classification. This system divides the pelvic cavity into specific zones, allowing doctors to pinpoint exactly where the disease is located, whether it is on the ovaries, deep in the pelvic floor, or near the bladder. By comparing the shape of the uterus to the specific location of the disease, the team sought to find a pattern that had previously gone unnoticed.

The study revealed that the shape of the uterus is indeed a strong predictor of whether a woman will have endometriosis or adenomyosis, and it dictates where that disease is likely to appear. Among the 304 women, those with a dysmorphic uterus, a shape that is distorted but not divided, had a very high rate of associated disease. In fact, half of the women with this specific shape showed signs of endometriosis or adenomyosis. Similarly, women with a septate uterus, where a wall of tissue divides the uterine cavity, also showed a high prevalence of the condition, with about 41.5 percent of them affected. In contrast, women with a bicornuate uterus, which looks like a heart with two horns, were much less likely to have the disease, with only about 16.7 percent showing signs of it. The researchers found that the risk of having endometriosis was five times higher for women with a dysmorphic uterus and more than three times higher for those with a septate uterus compared to women with the bicornuate shape. This suggests that the specific way the uterus is formed creates an environment that either encourages or discourages the growth of this tissue.

Beyond simply predicting who has the disease, the study uncovered a striking difference in where the disease settles based on the uterine shape. For women with a dysmorphic uterus, the disease was most frequently found in the FA compartment, a zone that includes the bladder and the area where the uterine lining grows into the muscle wall. This points toward a mechanism where the abnormal shape and movement of the uterus might push tissue directly into the muscle or nearby bladder area. On the other hand, women with a septate uterus were most likely to have deep infiltrating endometriosis, a severe form of the disease that spreads into the deep tissues of the pelvis, including the ligaments and the space between the vagina and rectum. This distinction is crucial because it implies that the physical mechanics of a septate uterus might be driving the tissue deeper into the pelvic floor, whereas a dysmorphic uterus might be linked more to issues within the muscle wall itself. Interestingly, the study found no significant link between the shape of the uterus and the presence of endometriosis on the ovaries, suggesting that ovarian disease might be driven by different factors, such as genetics or hormones, rather than the shape of the uterus.

The researchers also looked at the most severe cases of uterine malformation, where the uterus is missing or barely formed, and found that none of these women had endometriosis. This makes biological sense, as the disease requires menstrual tissue to flow backward to establish itself; without a functional uterus and menstrual flow, the condition cannot develop. The findings from this study are significant because they move beyond simply identifying that a link exists to showing exactly how the link works. The data suggests that the specific architecture of the uterus influences not just the likelihood of developing endometriosis, but also the specific territory the disease will occupy. This means that when a doctor identifies a woman with a septate or dysmorphic uterus, they should be particularly vigilant for specific types of endometriosis. By using advanced ultrasound to see both the shape of the uterus and the map of the disease at the same time, medical teams can plan more effective treatments. The study concludes that understanding these patterns allows for a more personalized approach to care, ensuring that the surgical or medical plan addresses the specific risks associated with a woman's unique anatomy.