PMOS (formerly PCOS) 101

This year, following a 14-year international campaign involving women, doctors and health organisations, PCOS (polycystic ovary syndrome) was officially renamed polyendocrine metabolic ovarian syndrome, (PMOS for short) a name that better reflects the fact that this is a condition affecting much more than the ovaries.

Around 1 in 8 women are thought to have PMOS, and it’s estimated that up to 70% may be undiagnosed. PMOS is a complex endocrine, metabolic and reproductive condition that can affect ovulation, hormones, metabolism, and both mental and physical health.

When your ovaries are getting ready to release an egg, they develop small fluid-filled sacs called follicles, each containing an immature egg. Normally, one follicle becomes dominant and releases an egg during ovulation.

Some women with PMOS have what’s called polycystic ovarian morphology -essentially, a higher number of small follicles visible on an ultrasound. These aren’t the same as the cysts you might get elsewhere in the body, and not everyone with PMOS has this ovarian appearance.

Why the name change?

The name PCOS had two main problems. Firstly, the term ‘polycystic’ suggested that affected ovaries were riddled with cysts, when what we’re actually talking about is an increased number of small follicles and not everyone with the condition has them.

The second problem was that by putting so much emphasis on the ovaries, the name didn’t really capture the fact that this is a hormonal, metabolic and reproductive condition that can affect the whole body. Unsurprisingly, this confusion and naming structure previously contributed to people not always recognising the condition, delayed diagnosis and/or women not getting the right care.

P.S. If you already have a diagnosis, the underlying condition hasn’t suddenly changed because of the name. Existing diagnoses remain valid and current treatments remain the same!

Common symptoms of PMOS

Women can experience PMOS very differently, some have few or no obvious symptoms and symptoms can also change over time. If you do have symptoms of PMOS, they can include:

• irregular periods or no periods at all

• oily skin and acne

• difficulty getting pregnant

• excessive body or facial hair

• thinning hair or hair loss

• weight gain or difficulty managing weight

• tiredness or fatigue

• changes in mood or mental health (such as anxiety and depression)

• metabolic problems such as insulin resistance

Getting a diagnosis from a doctor or clinician can be frustratingly slow.

For adults, PMOS is generally diagnosed when two of three features are present: problems with ovulation or irregular periods, signs of higher androgen levels (such as testosterone - either seen through symptoms such as excess hair growth or confirmed through blood tests), and/or a particular appearance of the ovaries on ultrasound.

For adults, AMH can also be used instead of an ultrasound to assess for polycystic ovarian morphology, although AMH shouldn’t be used on its own to diagnose PMOS. Other possible causes of the symptoms also need to be ruled out.

If you’re concerned, it’s definitely worth pushing for answers. PMOS is associated with a higher risk of things including type 2 diabetes, high blood pressure and cardiovascular risk, as well as an increased risk of endometrial (womb lining) cancer.

The most useful thing you can do is keep track for a few months of when your periods start and anything else you’ve noticed - skin, hair, energy, sleep, mood, etc. - then take it with you and ask your GP directly whether PMOS could be the cause.

If you’re on the pill, it’s worth remembering that the monthly bleed you get isn’t the same as a natural menstrual period, so it won’t necessarily tell you what your natural cycle is doing. The pill can also affect some hormone measurements, so your doctor can advise on whether and when testing is appropriate if you’re being assessed for PMOS.

What causes PMOS?

Frustratingly, we still don’t know exactly what causes PMOS. What we do know is that it’s complex and multifactorial, involving genetics, hormones, metabolism and the way the ovaries and other tissues respond to those signals.

Many people with PMOS have higher levels or activity of androgens such as testosterone (often called a ‘male’ hormone, although testosterone is naturally produced by women too). Insulin resistance and higher insulin levels can also contribute to increased androgen production.

LH (luteinising hormone) is involved in ovulation and ovarian hormone production too, and some people with PMOS have altered LH signalling - although having a high LH level isn’t required to have PMOS.

SHBG (sex hormone-binding globulin) is a protein that binds to sex hormones including testosterone. Lower SHBG can mean that more testosterone is available to have an effect on the body, and lower levels are common in PMOS, particularly alongside metabolic problems.

The exact reason these changes happen isn’t fully understood. PMOS can run in families and clearly has a genetic component; researchers have identified lots of genetic variants associated with the condition, but there isn’t one single ‘PMOS gene’ that causes it.

Finally, insulin resistance isn’t simply the cause of PMOS. It’s one of the metabolic features that can be involved, and the relationship between hormones, insulin and the ovaries is complicated.

What can help?

At the moment, there’s no cure for PMOS, but there are lots of ways to manage the symptoms and reduce some of the associated health risks. Treatment can include lifestyle changes, nutrition, exercise, hormonal contraception, medication and fertility treatments, depending on what symptoms and health concerns someone has. There isn’t a single treatment plan that works for everyone.

The first things to consider are often lifestyle and nutrition based:

Food

There is no single ‘PMOS diet’ that everyone needs to follow and it definitely doesn’t need to be restrictive! In fact, international guidelines specifically recommend avoiding unnecessarily restrictive or nutritionally unbalanced diets.

Your body needs all three macronutrients - fat, protein and carbohydrates - alongside the vitamins, minerals and other nutrients it needs to function properly.

Rather than demonising individual foods, think about the overall quality and balance of your diet. A generally nutritious, sustainable eating pattern can support metabolic health and help manage some PMOS-related symptoms, particularly when insulin resistance is present.

Exercise

Movement and exercise can really help improve insulin sensitivity and metabolic health. Even short periods of movement, including walking after meals, can help reduce blood glucose spikes. Over time, regular physical activity can support insulin sensitivity and cardiovascular health.

Try to get a good mix of strength and cardio throughout the week in a way that suits your preferences, your body and your life - just like nutrition, there isn’t one type of exercise that’s magically ‘better’ for PMOS.

Sleep

Sleep is a big helper when it comes to managing your overall health with PMOS!

Aim for around 7–9 hours a night, sleep-time consistency and sleep quality/hygiene. Poor or disrupted sleep can affect things like appetite regulation, mood and metabolic health, and be aware that sleep problems are also more common in people with PMOS.