PCOS has officially been renamed — and for the millions of people living with the condition, it’s a change that has been a long time coming. After more than a century marked by inaccurate, misleading, and outdated labels, one of the most common hormone disorders in the world finally has a name that actually reflects what it is.

A New Name After 14 Years of Work

Polycystic ovary syndrome (PCOS) should now be known as polyendocrine metabolic ovarian syndrome, or PMOS, according to a global science consortium.

The new name was announced this week at the European Congress of Endocrinology in Prague. It is the result of 14 years of collaboration between healthcare experts, patients, and advocates — led by Verity, a UK-based charity, Australia’s Monash University, and the international Androgen Excess and PCOS Society.

The reasoning behind the change is blunt. The team behind the initiative has described the term PCOS as long recognized to be inaccurate and potentially harmful, arguing that the old name reflects only one organ and fails to capture the disorder’s true multisystem nature.

For the transition period, the consortium has said the terms PCOS and PMOS will remain interchangeable for the next three years.

Why the Old Name Was a Problem

To understand why this matters, it helps to look at how the condition got its name in the first place — and how that name was wrong from two different directions.

Named After Two Men, Then a False Premise

The “cysts” behind polycystic ovary syndrome first drew widespread attention in 1935, when two Chicago surgeons, Irving Stein and Michael Leventhal, were investigating infertility in women.

During surgery, they noticed their patients’ ovaries were enlarged and contained numerous small, cyst-like structures. When they removed these “cysts,” they reported that menstrual cycles resumed, and some patients went on to have biological children. At the time, science was only just beginning to understand how ovulation worked — sex hormones like estrogen and progesterone had only recently been discovered.

In 1958, Stein published an article naming the diagnosis Stein-Leventhal Syndrome and claimed it could be cured with surgery. Later, it became widely known as PCOS.

The “Cysts” Were Never Really Cysts

Here’s the deeper flaw: those “cysts” turned out to be something else entirely. They were actually ovarian follicles — underdeveloped eggs — that had simply stopped growing.

Today, we know these immature follicles aren’t a unique feature of the condition at all, and they rarely require surgical removal. In fact, some patients with PMOS don’t even show evidence of them on ultrasounds.

Terhi Piltonen, an obstetrician and gynecologist in Finland involved in the name change, has called the term PCOS “confusing.” She explained that many women — and even professionals — believe the ovary contains large cysts that can burst or need surgery. The reality, she said, is that the ovary is “full and lush,” carrying a high reserve of small, underdeveloped follicles. That misplaced focus on the ovaries, she noted, has caused real harm, leading to women being ignored when they raised concerns about weight, metabolic problems, mental distress, and skin symptoms.

A Condition That Goes Far Beyond the Ovaries

One of the biggest misconceptions is that PMOS is purely a reproductive disorder that begins in the ovaries. While infertility can be a struggle for some patients, that isn’t always the case — and research suggests the condition’s effects extend far beyond the ovaries, possibly even starting in the brain.

PMOS can cause a wide range of symptoms, including:

• Irregular menstrual periods and abnormal ovulation
• Excess facial or body hair and acne
• Endocrine, metabolic, psychological, and dermatological issues
• Infertility, in some cases

Crucially, many of these effects can persist well beyond a person’s reproductive years.

The scale of the condition is enormous. PMOS affects roughly 170 million people worldwide, and it’s estimated that up to 70 percent of patients go undiagnosed. The misleading name may well be part of the reason why.

Why “Metabolic” Matters

Perhaps the most important word in the new name is “metabolic.” The change is meant to highlight a side of the condition that has been badly overlooked.

Consider the numbers:

• As many as 85 percent of patients with PMOS are estimated to experience insulin resistance.
• They also face a higher risk of type 2 diabetes, obesity, and fatty liver disease.
• Despite this, patients are often not screened properly for these conditions.

The history of research reflects this blind spot. From 1935 through the 1970s, study focused mostly on the hormonal aspects of the condition. Only in the last two decades of the 20th century did attention shift toward metabolic issues involving hormones like insulin.

A turning point came in 2000, when one of the first randomized, double-blind, placebo-controlled studies investigated whether the diabetes drug metformin could treat symptoms. The results were encouraging — metformin significantly reduced circulating insulin and testosterone levels.

A Diagnosis and Treatment Gap

Even with that progress, care remains inconsistent. There is still no known cause or cure for the syndrome, and treatments vary widely between individuals, though hormonal, metabolic, and surgical options exist to improve quality of life.

The problem is access. Drugs like metformin are still frequently prescribed “off-label” for PMOS, meaning they aren’t officially approved for it — and therefore often aren’t covered by insurance or government programs. In the US, for example, that can leave patients paying hundreds of dollars a month out of pocket.

As endocrinologist Blazej Meczekalski argued in a 2023 editorial, the term PCOS is “misleading, confusing,” and projects a negative image onto patients. Advocates hope the new name will help fix that.

The Bottom Line

The fact that PCOS has officially been renamed PMOS is more than a cosmetic update — it’s an attempt to correct nearly a century of scientific misdirection. Patient advocate Lorna Berry, who worked on the initiative, said she hoped the change would lead to better outcomes for women across their lifetime, noting that those living with the condition have long had to fight for diagnosis amid abundant misinformation.

By shifting the focus away from “cysts” that were never cysts, and toward the metabolic reality of the disorder, the new name could finally help steer researchers, insurers, government agencies, doctors, and patients toward the care that’s actually needed.