Health Resources Women's Health

What’s the Difference Between PMOS and Endometriosis?

June Lawver
June Lawver · December 6, 2024
6 min read · Sources Verified
Medical review by Kat McGraw MD
Updated: May 13, 2026
Endometriosis versus PCOS differences and similarities

Editor's Note (May 2026): This article may make references to PCOS (polycystic ovary syndrome) throughout, but the condition has since been officially renamed. Following a landmark global consensus study published in The Lancet in May 2026, polycystic ovary syndrome (PCOS) has been officially renamed polyendocrine metabolic ovarian syndrome (PMOS). The previous name was considered inaccurate because it implied the presence of pathological ovarian cysts, obscured the condition's broader endocrine and metabolic features, and contributed to delayed diagnosis, fragmented care, and stigma. The new name better reflects that this is a complex, multisystem hormonal disorder.

PMOS and endometriosis are two reproductive health conditions that can cause irregular periods, fertility challenges, and hormonal imbalances. While PMOS stems from excess androgens (like testosterone), leading to irregular cycles, acne, and metabolic issues, endometriosis involves endometrial-like tissue growing outside the uterus, causing chronic pain and inflammation.

PMOS is a hormonal disorder often linked to ovarian cysts, irregular or absent periods, acne, excess hair growth, and metabolic issues like weight gain.

Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus, leading to severe pelvic pain, heavy bleeding, pain during sex, and gastrointestinal symptoms.

If you have concerns about your reproductive health, consult with a physician before taking action.

Venn diagram comparing endometriosis and PCOS
The Main Differences and Similarities Between Endometriosis and PMOS
*Ovarian cysts are not required for PMOS diagnosis. They can also be present in endometriosis in some cases.

Key Differences Between PMOS & Endometriosis

Primary Symptoms:

Hormonal Imbalances:

Key Similarities Between PMOS & Endometriosis

Menstrual Patterns:

Despite endometriosis and PMOS stemming from separate causes, both can cause skipped, irregular, or sporadic periods, heavy or continuous bleeding, spotting, etc.

Cyst Formation:

While PMOS is more commonly associated with cyst formation, there are some cases in which endometriosis patients form bumps or cysts on pelvic organs and on the ovaries.

Mental Health Issues:

Both conditions increase the risk of depression and anxiety. Additionally, those with PMOS are more likely to suffer from bipolar disorder and OCD, while those with endometriosis are genetically predisposed to eating disorders.

Infertility:

PMOS and endometriosis can both affect fertility, but they do so in different ways. PMOS vs endometriosis fertility primarily differs in that PMOS often disrupts ovulation, while endometriosis can cause scarring and inflammation that interfere with implantation.

Symptoms of PMOS and Endometriosis

PMOS Symptoms

PMOS symptoms arise from excess androgens, such as testosterone. These hormones, typically linked to male reproductive health, can lead to lighter or infrequent periods in individuals with PMOS.

Although men have higher testosterone levels, this hormone also plays a key role in women’s health. Testosterone is a precursor to estrogen and supports ovulation during the menstrual cycle.

When androgens are overproduced, they disrupt hormonal balance and contribute to hallmark PMOS symptoms.

Endometriosis Symptoms

Endometriosis symptoms are mainly associated with pain from excess endometrial-like tissue outside of the uterus. Painful symptoms occur because the hormones and chemicals released by the misplaced endometrial tissue can lead to inflammation and irritation in the pelvic organs. Typical symptoms of endometriosis include:

Menstrual Irregularities for PMOS vs Endometriosis

It’s common for endometriosis patients to experience heavy periods, whereas PMOS patients might experience lighter or missed periods. However, both PMOS and endometriosis have been known to cause irregular periods and/or heavy bleeding, and symptoms can vary among individuals.

If you’re looking for a comprehensive platform to keep track of your symptoms, cycle irregularities, and health records, feel free to check out Guava, an app built for those with chronic illnesses.

Can You Have PMOS and Endometriosis at the Same Time?

Yes, though PMOS and endometriosis involve opposite hormonal imbalances, some individuals are diagnosed with both. A 2023 study suggests that PMOS and endometriosis co-occur in about 2% and 5% of menstruating individuals.

Graphic depicting that between 2% and 5% of women get both endometriosis and PMOS
Endometriosis and PMOS Co-occurrence Rates in Menstruating Women

What the Research Found

These findings support the idea that PMOS and endometriosis stem from opposing hormonal imbalances. PMOS is driven by excess ovarian testosterone production, while endometriosis is linked to lower testosterone levels relative to estrogen.

How PMOS & Endometriosis Are Diagnosed

PMOS Diagnosis

PMOS is generally easier to diagnose than endometriosis, as it presents clearer clinical markers and is more straightforward once other conditions have been ruled out. It still takes 4.3 years on average, however, from the first time seeking medical care for PMOS-related symptoms to receiving a diagnosis. To be diagnosed with PMOS, you need to have at least two of four diagnostic criteria:

  1. Either infrequent or prolonged periods
  2. Excess androgens in the blood
  3. Excess facial/body hair, excessive acne, or thinning scalp hair
  4. Cysts on one or both ovaries

Despite its former name (polycystic ovarian syndrome, or PCOS), you don’t have to have ovarian cysts to have PMOS. Alternatively, ovarian cysts don’t always indicate PMOS.

Endometriosis Diagnosis

To diagnose endometriosis, doctors often rely on a combination of symptom assessment, medical history, and imaging techniques such as ultrasound or, occasionally, MRI to identify potential masses of endometrial tissue in the pelvic or vaginal region.

While these methods can suggest a diagnosis, the ‘gold standard’ for ruling out endometriosis is a surgical examination, typically via laparoscopy. Laparoscopic surgery involves a small abdominal incision to directly visualize and confirm the presence of endometrial tissue outside the uterus. Laparotomic surgery, which requires a larger incision, is less commonly used for diagnostic purposes due to its invasiveness.

It’s important to note that surgical diagnosis is not always necessary to diagnose endometriosis. There are significant risks associated with pelvic and abdominal surgery, such as complications or prolonged recovery time, however, it’s a useful tool for accurate diagnosis.

Advances in non-surgical diagnostic methods aim to reduce reliance on surgery, providing safer options for patients while still addressing their symptoms. As of 2020, the global diagnostic delay for endometriosis remained lengthy, averaging between 7 and 9 years, highlighting the need for more accessible and efficient diagnostic resources.

PMOS vs Endometriosis Treatment: Best Options for Managing Symptoms

It’s important to consult with a health professional before starting any sort of treatment plan. Remember, everyone is different and something that works for someone else might not be the right fit for you.

PMOS Treatment

Icon representing lifestyle modifications for PCOS treatment. Icon representing hormonal contraceptive options for PCOS treatment. Icon representing Metformin, a medication used in PCOS management.

Management of PMOS focuses on alleviating symptoms, restoring hormonal balance, and addressing fertility concerns. Key treatment strategies for PMOS include:

Endometriosis Treatment

Icon representing oral medications for endometriosis treatment. Icon representing menstrual cycle tracking for endometriosis management. Icon representing surgical treatment options for endometriosis.

Treatment for endometriosis aims to relieve pain, slow the growth of or remove endometrial-like tissue, and enhance fertility outcomes. Options include:

In Summary

PMOS and endometriosis both impact reproductive health and fertility but differ in causes, symptoms, and treatments.

PMOS stems from hormonal imbalances like excess androgens, while endometriosis involves endometrial-like tissue growing outside the uterus, causing pain and inflammation.

Diagnosis and treatment also vary, with PMOS managed through hormonal balance and lifestyle changes, and endometriosis focusing on pain relief and sometimes surgical intervention.

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