The Overlooked Link: Allen-Masters Syndrome and Endometriosis
How a Little-Known Condition Can Complicate Diagnosis and Treatment for Women in Pain
The Overlooked Link: Allen-Masters Syndrome and Endometriosis
How a Little-Known Condition Can Complicate Diagnosis and Treatment for Women in Pain
What Is Allen-Masters Syndrome?
Allen-Masters Syndrome (AMS) refers to a condition where the ligaments that support the uterus become torn or stretched, often due to trauma or childbirth. The damage causes the uterus to become hypermobile, or “floppy,” which can lead to chronic pelvic pain, abnormal uterine positioning, and a range of gynecological symptoms.
First described in the 1950s by gynecologists Allen and Masters, the syndrome was initially observed in women who experienced difficult or forceful deliveries. However, it's now known that other pelvic trauma—such as surgeries, repeated inflammation, or even invasive endometriosis—can also play a role.
How It Feels: The Symptoms
The symptoms of AMS often overlap with other pelvic disorders, including endometriosis, which makes it incredibly hard to diagnose:
• Chronic pelvic pain, especially on one side
• Pain during intercourse (dyspareunia)
• A feeling of “heaviness” or dragging in the pelvis
• Irregular bleeding or spotting
• Referred pain to the lower back or legs
• Pain made worse by certain movements or positions
These symptoms can persist even after surgery for endometriosis or fibroids, leaving women frustrated and wondering why their treatments didn’t work.
The Complication with Endometriosis
Endometriosis and Allen-Masters Syndrome can coexist—and when they do, they complicate each other.
Endometriosis and Allen-Masters Syndrome can coexist—and when they do, they complicate each other.
Here’s how:
1. Mimicking or Masking Each Other
AMS pain can feel nearly identical to endometriosis. In laparoscopic surgery, torn ligaments or peritoneal defects might be mistaken for endometriosis—or missed entirely.
2. Worsening Each Other
The uterine instability caused by AMS may increase friction and inflammation in the pelvis, potentially exacerbating endometriosis symptoms. Likewise, the invasive nature of endometriosis can weaken uterine ligaments, creating a cycle of worsening pain.
3. Delaying Diagnosis
Because AMS isn’t well known, many surgeons focus only on excising visible endometriosis lesions. If ligament tears or pelvic instability aren’t also addressed, pain may persist despite "successful" surgery.
4. Influencing Fertility
While endometriosis is a known contributor to infertility, AMS can add to the challenge by altering the position of the uterus, interfering with sperm transport, or making embryo implantation more difficult.
Diagnosis: Why It’s Often Missed
AMS is best diagnosed through clinical examination and often requires a high index of suspicion from an experienced gynecologic surgeon. Imaging like MRI or ultrasound may not show ligament damage clearly. In some cases, laparoscopic exploration is the only way to confirm it, by observing a hypermobile uterus or peritoneal defects (like dimples or windows in the pelvic lining).
Unfortunately, many OB/GYNs are not trained to look for Allen-Masters Syndrome, which means it’s often overlooked—especially in patients already diagnosed with endometriosis
What Can Be Done?
If AMS is suspected, the treatment may include:
• Pelvic physical therapy to support surrounding muscles and reduce pain
• Surgical repair or suspension of the damaged ligaments, often during laparoscopy
• Pain management strategies including nerve blocks or hormonal regulation if endometriosis is also present
• Lifestyle modifications to reduce strain on the pelvis (avoiding certain exercises, managing constipation, etc.)
The Takeaway
Allen-Masters Syndrome may not be as well-known as endometriosis, but its impact is very real—especially for women who feel like they've tried everything and still have no answers.
If you’ve had surgery for endometriosis and your pain persists, or if your symptoms don’t quite fit the typical endo profile, it might be worth asking your doctor about Allen-Masters Syndrome.
Women deserve full answers—not partial relief.
Sources & Further Reading
• Howard FM. (2003). Chronic Pelvic Pain. Obstetrics and Gynecology
• Vercellini P et al. (2006). Chronic pelvic pain: pathogenesis and therapy. Best Practice & Research Clinical Obstetrics and Gynaecology
• Tu FF et al. (2017). Beyond Endometriosis: Recognizing and Treating Comorbid Pelvic Pain Disorders. Clinical Obstetrics and Gynecology
What Is Allen-Masters Syndrome?
Allen-Masters Syndrome (AMS) refers to a condition where the ligaments that support the uterus become torn or stretched, often due to trauma or childbirth. The damage causes the uterus to become hypermobile, or “floppy,” which can lead to chronic pelvic pain, abnormal uterine positioning, and a range of gynecological symptoms.
First described in the 1950s by gynecologists Allen and Masters, the syndrome was initially observed in women who experienced difficult or forceful deliveries. However, it's now known that other pelvic trauma—such as surgeries, repeated inflammation, or even invasive endometriosis—can also play a role.
How It Feels: The Symptoms
The symptoms of AMS often overlap with other pelvic disorders, including endometriosis, which makes it incredibly hard to diagnose:
• Chronic pelvic pain, especially on one side
• Pain during intercourse (dyspareunia)
• A feeling of “heaviness” or dragging in the pelvis
• Irregular bleeding or spotting
• Referred pain to the lower back or legs
• Pain made worse by certain movements or positions
These symptoms can persist even after surgery for endometriosis or fibroids, leaving women frustrated and wondering why their treatments didn’t work.
The Complication with Endometriosis
Endometriosis and Allen-Masters Syndrome can coexist—and when they do, they complicate each other.
Endometriosis and Allen-Masters Syndrome can coexist—and when they do, they complicate each other.
Here’s how:
1. Mimicking or Masking Each Other
AMS pain can feel nearly identical to endometriosis. In laparoscopic surgery, torn ligaments or peritoneal defects might be mistaken for endometriosis—or missed entirely.
2. Worsening Each Other
The uterine instability caused by AMS may increase friction and inflammation in the pelvis, potentially exacerbating endometriosis symptoms. Likewise, the invasive nature of endometriosis can weaken uterine ligaments, creating a cycle of worsening pain.
3. Delaying Diagnosis
Because AMS isn’t well known, many surgeons focus only on excising visible endometriosis lesions. If ligament tears or pelvic instability aren’t also addressed, pain may persist despite "successful" surgery.
4. Influencing Fertility
While endometriosis is a known contributor to infertility, AMS can add to the challenge by altering the position of the uterus, interfering with sperm transport, or making embryo implantation more difficult.
Diagnosis: Why It’s Often Missed
AMS is best diagnosed through clinical examination and often requires a high index of suspicion from an experienced gynecologic surgeon. Imaging like MRI or ultrasound may not show ligament damage clearly. In some cases, laparoscopic exploration is the only way to confirm it, by observing a hypermobile uterus or peritoneal defects (like dimples or windows in the pelvic lining).
Unfortunately, many OB/GYNs are not trained to look for Allen-Masters Syndrome, which means it’s often overlooked—especially in patients already diagnosed with endometriosis
What Can Be Done?
If AMS is suspected, the treatment may include:
• Pelvic physical therapy to support surrounding muscles and reduce pain
• Surgical repair or suspension of the damaged ligaments, often during laparoscopy
• Pain management strategies including nerve blocks or hormonal regulation if endometriosis is also present
• Lifestyle modifications to reduce strain on the pelvis (avoiding certain exercises, managing constipation, etc.)
The Takeaway
Allen-Masters Syndrome may not be as well-known as endometriosis, but its impact is very real—especially for women who feel like they've tried everything and still have no answers.
If you’ve had surgery for endometriosis and your pain persists, or if your symptoms don’t quite fit the typical endo profile, it might be worth asking your doctor about Allen-Masters Syndrome.
Women deserve full answers—not partial relief.
Sources & Further Reading
• Howard FM. (2003). Chronic Pelvic Pain. Obstetrics and Gynecology
• Vercellini P et al. (2006). Chronic pelvic pain: pathogenesis and therapy. Best Practice & Research Clinical Obstetrics and Gynaecology
• Tu FF et al. (2017). Beyond Endometriosis: Recognizing and Treating Comorbid Pelvic Pain Disorders. Clinical Obstetrics and Gynecology
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Your support can transform lives. Every donation helps us fund research, advocate for better care, and provide essential grants to women facing debilitating conditions.
Why Menopause Does Not Treat Endometriosis
Why menopause does not treat endometriosis
Quite often endometriosis patients are told to have their ovaries removed or put their activity on hold with hormonal medication as a way of treating the disease. As demonstrated by some studies, endometriosis lesions have the potential to produce their own oestrogen, as such removal of ovaries or temporary menopause will have little or no impact on the endometriosis itself.
What is oestrogen?
Various laboratory studies have shown that endometriosis is an oestrogen dependent disease. In females, the highest quantity of oestrogens is produced in ovaries. It is also produced in small amounts in other organs such as liver, heart and brain. The oestrogen is divided in three categories: E1 known as estrone, E2 known as estradiol and E3 known as estriol.
Out of all 3 oestrogen types the E2 is the most potent and it is active during the fertility period. E1 is more potent after the menopause and it is synthesised in adipose tissue from adrenal dehydroepiandrosterone, whilst E3 has a role in pregnancy, it’s produced by placenta during pregnancy, and it is the least potent one.
What is aromatase?
The conversion of androstenedione and testosterone E1 and E2 is done by the aromatase. Aromatase is expressed in places such as the brain, gonads, blood vessels, adipose tissue, liver, bone, skin, and endometrium. In fertile women the oestrogen biosynthesis takes place in the ovary, while in postmenopausal women it takes in extraglandular tissues such as adipose tissue and skin.
The role of aromatase expression in endometriosis
One of the first studies that have demonstrated the presence of aromatase expression in endometriosis implants was published in 1996.
To demonstrate the presence of aromatase in endometriosis implants, the scholars have conducted a study analysing and comparing biopsy samples from:
endometriosis implants from pelvic peritoneum (posterior cul-de-sac, bladder, and anterior cul-de-sac);
endometrial tissue in patients with histologically documented pelvic endometriosis;
pelvic peritoneal distal and normal endometrial tissues from women without endometriosis;
Based on the results, P450arom transcripts were detected in all endometriosis implants.The highest presence of P450arom was detected in endometriosis implants that involved the full thickness of the anterior abdominal wall. Also, in the core of the endometriosis implants, the P450arom transcript level was 4-fold higher than that in the surrounding adipose tissue. The authors concluded that the possibility of oestrogen production in endometriosis implants might promote their growth.
Other studies have also demonstrated a higher expression of aromatase in endometriosis implants. Zeitoun KM et al. concluded that molecular aberrations can impact the oestrogen biosynthesis leading to an increased local concentration of E2. The aberrant expressed aromatase in the endometriotic stromal cells converts C19, steroids to oestrogens.
Moreover, a immunohistochemical analysis found that the local estrogen production by aberrantly elevated aromatase takes place only in endometriosis and adenomyosis, and not in the normal endometrium.
In conclusion, removal of ovaries to stop the production of oestrogen as a way of treating endometriosis is not an efficient method, especially if endometriosis lesions are not removed. Endometriosis produces its own oestrogen and as long as the disease is left beyond it will continue to cause symptoms and impact organs.
-Athens Centre for Endometriosis
