PMOS, Formerly Known As PCOS.
Reviewed Dr Jo Mackson, MBBS FRACGP
Published May 2026
Reading time About 8 minutes
The name has changed. You haven’t.
As of May 2026, the name Polycystic Ovarian Syndrome or PCOS for short has finally been retired. So if you searched for PCOS and landed here, you are in the right place. The condition formerly known as polycystic ovary syndrome (PCOS) has been officially renamed polyendocrine metabolic ovarian syndrome, or PMOS for short. And while the new name is a mouthful, even more of a mouthful than the original (interesting choice), it is a much more honest description of what the condition actually is: a multi-hormone, metabolically driven condition that happens to involve the ovaries, rather than a condition of the ovaries themselves. So despite the tongue twister we are quietly very pleased about the change, and what it will mean for women with PMOS understanding their condition and getting the care they need to live well.
We use the new name throughout this guide, with the old one in brackets where it helps. Most importantly: if you have been told you have PCOS, you have PMOS. Nothing about your diagnosis, your treatment, or your body has changed. The name has just caught up with the science.
PMOS is one of the most common hormonal conditions affecting women. It affects around 1 in 8 women of reproductive age (and probably more, since up to 70% of women who have it are thought to remain undiagnosed). And yet, despite how common it is, for decades most women left their diagnosis with little more than a brief explanation and an alarming-sounding label, enough to plant a quiet worry about their fertility and a sense that their body had somehow done something wrong. The new name is a real step toward changing that. This guide is the next one.
If you take away just one thing from this Mini Guide, let it be this. PMOS is not your fault. It is heritable, written into your genes, and runs in families. Nothing you did caused it.
The old name, polycystic ovary syndrome, caused decades of confusion and anxiety. It was named after a sign of the condition, not the cause of it. It put the ovaries at the centre of the story when the ovaries are mostly bystanders. It used the word cysts for structures that are not actually cysts at all. And it left generations of women with a diagnosis that sounded scarier than it needed to and explained less than it should. The rename to PMOS, polyendocrine metabolic ovarian syndrome, finally says out loud what the science has been telling us for years: this is a multi-hormone, metabolically driven condition.
This Mini Guide is here to do something simple: explain what PMOS actually is, what it isn't, and what good care of it looks like.
The ‘M’ in PMOS, explained.
PMOS is a metabolic condition, and in most women it is driven by insulin resistance. It is not a primary condition of the ovaries. It is a condition in which the cells of your body do not respond properly to insulin, the hormone that controls how your body uses carbohydrates and manages your blood sugar.
A quick insulin 101. When you eat a meal containing carbohydrates, your body breaks the carbs down into glucose (sugar) and absorbs it into your bloodstream. Glucose is the fuel your cells run on, but it cannot stay in the blood for long without causing damage. So your pancreas, an organ tucked behind your stomach, releases insulin to clear the glucose out of your blood and into the cells where its needed.
Think of insulin as a key. When your blood sugar rises after eating, insulin travels through your body and unlocks your cells, letting the sugar move out of your blood and into them, where it is either used for energy straight away or stored for later.
In insulin resistance, like in PMOS, the locks get stiffer. The key still fits, but it sticks, and it takes a few more turns to open the door. So the sugar lingers in the blood for longer, and the pancreas, noticing it hanging around, responds by sending more insulin. At this point, we need to retire the lock and key, because the complexity of the human body refuses to fit a single tidy analogy. So let’s think about insulin instead as a cup of coffee. For a healthy person, a skim latte in the morning is enough to get going for the day. But if you’d had a late night, or you’re running on empty in the middle of a big project, one cup isn’t going to cut it. You might need two, three, even four double espressos to get the same lift. Let’s call these people insulin resistant. And just like the extra coffee, you do eventually get the effect you were after. Coffee gets you your energy; insulin gets your blood sugar into the cells.
But all that extra caffeine racing through your system can do more than just wake you up. You might get the shakes, a headache, a racing heart. In the same way, excessively high insulin levels don’t quietly work on glucose alone. They have knock-on effects elsewhere in the body, in the liver, the brain, and the ovaries.
Each of these effects maps onto one of the three Rotterdam Criteria that doctors use to diagnose PMOS, which we cover in the Deep Dive.
The result of all three together is the cluster of features that defines PMOS: irregular or absent periods, signs of androgen excess like acne, excess facial and/or body hair, and scalp thinning, and longer-term changes in metabolic health.
"PMOS is a metabolic condition with reproductive side effects, not a reproductive condition with metabolic complications. The new name finally says it out loud."
It is not just semantics. Treating PMOS as an ovary problem alone misses the point. The cycle is the visible part, but the metabolic part is where the work needs to happen.
The questions we hear most often.
After a PMOS diagnosis, the same handful of questions tends to come up first. Here are the three we hear most.
We said it before, and we will say it again. You did not cause your PMOS. It is heritable, written into your biology before you were born. Thats not to say that there are lifestyle factors that matter for managing it, and for some women, managing it well enough that they barely notice they have it. But there is no diet, exercise, or supplement that could have prevented it, as PMOS cannot be prevented, and it cannot be cured. It is the genetic hand you were dealt, like so much of what we see in medicine.
This is the most anxiety-laden question after a diagnosis. Most women with PMOS who want to have children do, either naturally or with support. PMOS is the most common cause of “anovulatory infertility”, which simply means infertility related to problems with ovulation, but it is also one of the most treatable. Around 70% of women with PMOS experience difficulty conceiving, due to ovulation being irregular or not happening at all. But not all of these women need fertility support, and the large majority never need IVF. Many conceive spontaneously, and many others conceive with simpler fertility treatments, such as oral medication to induce ovulation alongside ultrasound tracking to get the timing right. IVF is usually only needed when ovulation induction has not worked, or where there are other factors at play such as blocked tubes, significant sperm issues, advanced reproductive age, or where genetic testing of embryos is needed.
The pill is one of the most misunderstood parts of PMOS care, and most of what circulates online is wrong. Because of this, we couldn’t just pick one, so here are the three loudest claims, and what is actually true.
'The pill caused my PMOS.' No. PMOS is heritable, written into your biology before you were born. No medication causes it.
'The pill is masking my PMOS.' Masking is a social media term, not a medical one. The pill is a treatment for some PMOS symptoms, and it works while you take it: it regulates your cycle, improves androgen-driven symptoms like acne and excess hair, and protects the lining of the uterus from building up. Treating something is not the same as hiding it. A medication that makes symptoms lessen or disappear without causing harm is doing its job, not concealing the condition. The myth comes from the fact that when women stop the pill, the underlying PMOS becomes visible again. That is not the pill having hidden something dangerous. That is proof the pill was working.
‘Why did my PMOS get worse when I stopped the pill?' Just as we said above, when you stop the pill, your PMOS returns as it was, because the pill was treating the symptoms, not curing the underlying condition. The contrast between feeling well on the pill and feeling unwell off it can make it seem like things got worse, but the pill did not cause that. The condition simply became visible again.
What good PMOS care actually looks like.
Good care starts with getting the diagnosis right. Whether you suspect you have PMOS but have never been formally investigated, you have a diagnosis but feel you were handed a label without a plan, or you have been told you have PMOS and something about it does not quite add up, the starting point is the same: a proper diagnostic workup.
A proper PMOS workup does more than confirm the diagnosis. Several conditions can look almost identical to PMOS on paper, including thyroid dysfunction, elevated prolactin, premature ovarian insufficiency, and functional hypothalamic amenorrhoea. Ruling these out is the first part of getting the diagnosis right.
Next we get a clear picture of where your metabolic health sits: blood tests for glucose, insulin, lipids, and liver function, alongside height, weight, BMI, and waist circumference. Together these give us the baseline against which the long-term picture is tracked.
This process also helps us identify which of the four PMOS phenotypes you have, because PMOS does not look the same in every woman, and knowing your phenotype shapes which symptoms to expect and which treatments are most likely to help. If you want to know more about phenotypes, our PMOS Deep Dive walks through all four phenotypes properly.
Once we have confirmed your diagnosis, identified your phenotype, and assessed your metabolic health, we work out which parts of your PMOS are actually bothering you. PMOS looks different in every woman, and can affect skin and hair, weight and metabolism, periods and cycle regularity, fertility, mood and mental health, and long-term cardiovascular and diabetes risk. Different women also have very different priorities. With all of that on the table, we build a management plan matched to you specifically. There is no single PMOS treatment plan. There’s just a toolkit, from which we can use whatever treatments we need to help with the symptoms bothering you most, whether you are currently trying to conceive or actively avoiding it, and where you sit metabolically.
Two things in the PMOS toolkit are non-negotiable for every patient: nutrition and movement. These are not optional. PMOS is a metabolic condition, and as such it responds to what and how we eat and when and how we move. Movement and nutrition are of course important for every woman, but in PMOS even more so. That said, lifestyle alone does not completely manage PMOS for most women. But unfortunately, with no magic tablet to replace a Mediterranean diet and two resistance sessions a week, and with the treatments we do have only able to do so much, lifestyle remains the most important foundation you can build for your PMOS.
On top of the lifestyle foundation, treatment options include hormonal approaches like the combined pill for cycle regulation and androgen-driven symptoms, insulin-sensitising medications like metformin for the metabolic side, ovulation support when fertility is the goal, and targeted treatments for specific symptoms like acne or unwanted hair.
If you average fewer than 6 periods a year and you are not on hormonal contraception (pill, implant or IUD), this is worth a review. The lining of the uterus is designed to turn over regularly. When periods are too far apart, the lining doesn't get a chance to turn over and instead can build up over time. This is a known risk factor for endometrial cancer, which is rare, but is more common in PMOS patient. For many women with infrequent periods, these can feel like one of the few welcome things about having PMOS, which is exactly why this part of management often gets overlooked. But please do raise this with your GP, ideally one familiar with PMOS, even if the periods themselves are not bothering you.
PMOS is a lifelong condition, but it is one of the more manageable ones in women's health. With good care, symptoms can settle, long-term metabolic risks can be reduced, and the implications for fertility, while real, sit much closer to manageable than what your 3am Google spiral led you to believe.
So there you have it. Our Mini Guide on PMOS. If we've left you feeling at all curious about the deeper science, or wanting a proper walk through the phenotypes and management options, our Deep Dive is where to go next.
This Mini Guide is just a taste test of PMOS. The Deep Dive is the full degustation. It covers every tasty morsel: the details of diet and movement that actually shift insulin resistance, the AMH question that trips up almost everyone (including some doctors), and the fertility section that most women want to read first.
It is long. It is detailed. It is the education on this condition we think every woman should have had years ago. We are not going to insist you read it. Life is busy, and 'long-form medical education' is not on every woman's reading list. But if you ever find yourself wondering, the Deep Dive is here when you are. Your PMOS, Explained.