What Is PMOS and Why PCOS Is Being Replaced by PMOS

What Is Polyendocrine Metabolic Ovarian Syndrome (PMOS)

Polyendocrine metabolic ovarian syndrome (PMOS) is the new name for what, until recently, was known as polycystic ovary syndrome (PCOS). This change was established through a global consensus published on June 6, 2026, in The Lancet (1). This extensive body of work combined worldwide surveys, terminology assessments, and close collaboration with patient advocacy groups. The purpose of the terminology change is to accurately reflect the organic complexity of the condition, helping to ensure precise diagnoses and effective treatments.

Why the Change from PCOS to PMOS?

The term PCOS caused significant diagnostic confusion. Many women were incorrectly diagnosed simply for having multiple follicles visible on ultrasound, while others suffered from the syndrome without having “cysts.” These so-called “cysts” are actually normal follicles that have stopped developing due to hormonal imbalances.

The change in terminology reflects the need to accurately represent this condition and to improve both diagnosis and subsequent treatment.

Symptoms of PMOS

As its name indicates, this disorder involves metabolic and hormonal changes, which may present as:

• Menstrual disorders and anovulation: This presents as longer intervals between periods or even the absence of menstruation (amenorrhea).
• Excess androgens or hyperandrogenism: The increase in male hormones leads to acne (due to increased skin oil production), hirsutism (excessive facial and body hair growth), and sometimes androgenic alopecia (male-pattern hair loss).
• Insulin resistance and metabolic factors: In this metabolic syndrome, the female body cannot use insulin efficiently, which leads to weight gain and central obesity. In addition, up to 80% of women with this condition may have insulin resistance, which increases the likelihood of developing type 2 diabetes.
• Polycystic ovaries on ultrasound: It is important to understand that many women diagnosed with PMOS may not have polycystic ovaries, and not all women with this ultrasound appearance have PMOS. To confirm the diagnosis, other biochemical and clinical criteria must also be present.

Can PMOS Affect Fertility?

Polyendocrine metabolic ovarian syndrome is one of the most common causes of difficulty conceiving in women.

Irregular periods make it difficult to pinpoint the exact time of ovulation, and many women in this situation may not ovulate at all (anovulation), which makes achieving fertilization and subsequent pregnancy very difficult.

Insulin resistance and elevated male hormone levels, among other metabolic changes, have the potential to affect egg quality and impair its function.

When it comes to implantation, it is essential that the endometrium maintain proper receptivity. Irregular cycles and hormonal disorders can affect this.

Although PMOS-related changes increase the difficulty of conceiving, early diagnosis and personalized treatment significantly minimize this obstacle.

How Is PMOS Diagnosed?

To diagnose PMOS, at least two of the following three criteria must be met:

• Hyperandrogenism: Shown through an altered hormone profile with high levels of male hormones, or clinically through hair loss, severe acne, and hirsutism.
• Ovarian dysfunction: Irregular menstrual cycles, infrequent periods (oligomenorrhea), or even the absence of menstrual bleeding (amenorrhea).
• Polycystic ovarian morphology or elevated anti-Müllerian hormone (AMH): “Polycystic ovaries” are not, strictly speaking, ovaries with cysts; in fact, these “cysts” are nothing more than follicles that have stalled in their development due to a hormonal imbalance.

In addition, confirming the diagnosis requires ruling out any other condition with similar symptoms and clearly establishing a differential diagnosis with:

• Thyroid problems (hypothyroidism)
• Adrenal hyperplasia
• Hyperprolactinemia
• Cushing’s syndrome
• Androgen-secreting tumors

Treatment for PMOS

Treating polyendocrine metabolic ovarian syndrome requires a personalized, multidisciplinary approach involving specialists in endocrinology, gynecology, nutrition, sleep medicine, and psychology.

PMOS treatment focuses on modifying lifestyle habits, improving insulin sensitivity, regulating the menstrual cycle, reducing androgen levels, and, if desired, achieving pregnancy.

• Lifestyle changes. This is the cornerstone of treatment, particularly regarding physical activity and nutrition. Weight loss significantly improves the metabolic and hormonal profile.
• Pharmacological treatment. If symptoms persist despite lifestyle changes, oral contraceptives are used to regulate menstrual cycles. In addition, for their antiandrogenic effect, if that is not enough, spironolactone can be used to block androgenic effects.
• Metformin or GLP-1 analogues may be used to address metabolic symptoms, such as improving insulin sensitivity. These medications help comprehensively manage metabolism and reduce weight in people with obesity and glucose disorders. For those wishing to become pregnant, ovulation induction agents such as gonadotropins, clomiphene, or letrozole may be used.
• Long-term metabolic follow-up: Always with prior monitoring and ongoing check-ups by a specialist.

Frequently Asked Questions

Can I Get Pregnant With a PMOS Diagnosis?

At least 60% of patients diagnosed with PMOS are able to achieve a spontaneous pregnancy. Otherwise, a qualified professional would need to evaluate the case and personalize appropriate treatment.

How Do I Know If I Have PMOS or Just Cysts?

The imaging diagnosis of “polycystic ovaries” is made by ultrasound, whereas PMOS is a systemic condition that includes “polycystic ovaries,” metabolic disorders, and hormonal imbalances. To distinguish between the two, your gynecologist will need to carry out the necessary tests and establish an appropriate differential diagnosis.

What Happens If PMOS Is Left Untreated?

Without appropriate treatment for PMOS, serious metabolic problems may arise, such as high blood pressure, type 2 diabetes, increased risk of heart attack, and greater cardiovascular risk due to elevated cholesterol. Without normal menstrual cycles, the endometrium may thicken chronically, potentially increasing the risk of endometrial cancer over time. There is also a higher risk of infertility and a greater likelihood of pregnancy-related complications, such as gestational diabetes, miscarriage, or preeclampsia. Finally, mental health can also be affected, with an increased risk of chronic anxiety and depression.

What Should I Avoid Eating If I Have PMOS?

The goal of a diet for women with PMOS is to control the glucose spikes caused by insulin resistance and to follow an anti-inflammatory eating pattern. To do this, it is important to reduce consumption of:

• Total sugar: Cut out sodas, packaged juices, sweets, and pastries.

• Refined white flours: Replace white rice, pasta, and bread with their whole-grain equivalents.

• Fried and ultra-processed foods: Avoid low-quality cold cuts, fries, and fast food.

• Alcohol: Reduce it as much as possible, since it affects your hormones and liver.

• Dairy products: If you suffer from severe acne, reduce cow’s milk and opt for kefir or Greek yogurt instead.

It is important to eat real foods (vegetables, clean proteins, and healthy fats) and to avoid packaged products with labels full of chemical ingredients.

1. Teede H. et al. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process. The Lancet, 2026; 407, 2329-2339

Dr. Carlos Alvarado. Medical Coordinator of Instituto Bernabeu Cartagena.

Other links of interest: Fertile days calculator