Lead 

From PCOS to PMOS: Why the Name Is Changing, and What It Gets Right

Body Clock Podcast, Episode 1 · with Dr. Herman Weiss and host Daniel Kaufman, President of Circady Health

For about 90 years, one of the most common hormonal conditions in women has carried a name that points at the wrong thing. In the first episode of the Body Clock Podcast, Dr. Herman Weiss, an OB-GYN with more than 25 years of experience, tells host Daniel Kaufman what "polycystic ovary syndrome" or PCOS gets wrong, and why the field is moving to a new name: polyendocrine metabolic ovarian syndrome, PMOS.

"Well, it actually has nothing to do with cysts, and it has nothing really to do with ovaries. Ovaries are more of a symptom of it." — Dr. Herman Weiss

It's also a  common event. Dr. Weiss puts it at roughly 1 in 8 to 1 in 10 women. The World Health Organization estimates it affects 10–13% of women of reproductive age, and that up to 70% of women with it are undiagnosed.

In 1935, Irving Stein and Michael Leventhal reported on seven women with absent periods (amenorrhea) whose ovaries looked full of small cysts. The name that followed described what they could see. It didn't explain what caused it.

That's where the episode starts. In Dr. Weiss's view, the ovaries show the effect of a hormonal and metabolic problem that begins elsewhere in the body.

In May 2026, a new name arrived that also leads with hormones and metabolism. After a consensus process involving more than 50 patient and professional organizations, published in The Lancet, the condition is being renamed polyendocrine metabolic ovarian syndrome (PMOS). The Endocrine Society notes that the old name was misunderstood as "all about ovarian cysts.". The new name is being phased in over a three-year transition.

Dr. Weiss walks through what normally happens in a cycle. The brain sends a hormonal signal, and the ovary answers by maturing and releasing one egg. In this condition, he explains, the ovary doesn't respond to that signal cleanly. Instead of one follicle maturing, many are stimulated at once and stall partway through development.

Those stalled follicles are the ring of small "cysts" that shows up on an ultrasound, the picture clinicians long read as the condition itself. Daniel sums it up on the episode: "the result, not the cause. And the cause is much deeper."

If the ovary isn't where it starts, what is? Dr. Weiss names three drivers he sees in practice:

In his experience, there's also no symptom checklist. Irregular bleeding, acne, hair changes, weight changes, cravings, fatigue and brain fog can come and go with stress, sleep, alcohol and exercise. As he puts it: "They can have all of the above. None of the above, some of the above today and then tomorrow."

Dr. Weiss is direct about how his own field has handled the condition. For years, he says, care came down to two options: a birth control pill for patients who weren't trying to conceive, and IVF medication for those who were. The question of cause was often left unanswered in between.

"If a patient came to your office with these complaints and she didn't want to get pregnant, you gave her birth control pill and you got her out of your office." — Dr. Herman Weiss.

By the numbers/data in the podcast

Check the episode

Forward it along. It takes ten seconds and means a lot to us.