PCOS / PMOS
PCOS, diabetes and metabolic syndrome
Recognizing insulin resistance, diabetes and fatty liver early
Metabolism is a central part of polycystic ovary syndrome. This is exactly why, since 2026, the syndrome has had a new international name: PMOS, Polyendocrine Metabolic Ovarian Syndrome. The word “metabolic” in the name makes clear that PCOS/PMOS does not only affect the cycle and the ovaries, but the sugar and fat metabolism of the whole body.
Many metabolic changes start early and cause no symptoms for a long time. A woman can feel healthy while diabetes or a fatty liver develops over the years. An early assessment is therefore one of the most important measures in PCOS.
What is insulin resistance?
Insulin allows sugar to move from the blood into the cells. In insulin resistance, the cells respond less well to insulin. At first the body makes up for this by producing more insulin. Blood sugar then stays normal for a long time, but the high insulin level acts on many organs. It increases the production of androgens in the ovaries, disturbs ovulation and promotes the storage of fat in the belly and in the liver.
Insulin resistance in PCOS is partly inborn and independent of weight. In a study using the most accurate method of measurement, about 75% of slim women with PCOS had insulin resistance, and almost all women with a higher weight. A higher weight makes insulin resistance worse, but it is not its only cause.
How high is the risk of diabetes?
Women with PCOS have about a three times higher risk of impaired glucose tolerance and type 2 diabetes than women without the syndrome. Diabetes also often appears earlier in them, sometimes as early as the age of 30 or 40. The risk is highest with a higher weight, but it also exists with a normal weight. Ethnic background plays a role as well. Women of Asian background, for example, have a higher risk even at a lower weight.
A 2025 study from the UK Biobank compared women with PCOS with women of the same age and the same weight. Even at the same weight, the risk of type 2 diabetes was about 50% higher in PCOS. The syndrome itself is therefore a risk factor of its own.
Which test is right?
The guideline recommends a blood sugar assessment in all women with PCOS at diagnosis, regardless of age and weight. The most accurate method is the oral glucose tolerance test, in which blood sugar is measured fasting and two hours after a sugar drink. Fasting blood sugar and the long-term sugar value HbA1c are simpler, but they miss some women with impaired glucose tolerance.
After that, the doctor repeats the test every one to three years, depending on the risk. The risk is higher with a higher weight, previous raised blood sugar values, a history of gestational diabetes, diabetes in the family, high blood pressure and certain ethnic backgrounds. Before pregnancy and before fertility treatment, a glucose tolerance test is especially important.
A visible sign of insulin resistance is a dark, velvety discoloration of the skin on the neck, in the armpits or in the groin (acanthosis nigricans). This sign is a reason for a careful metabolic assessment.
What about diabetes in pregnancy?
Women with PCOS have a clearly higher risk of diabetes in pregnancy. Gestational diabetes increases the risks for the mother, such as pre-eclampsia and cesarean section, and for the child, such as a high birth weight, difficulties during birth and low blood sugar after birth. It is at the same time a warning sign of type 2 diabetes later in life. For this reason, the woman needs regular check-ups after birth. The guideline also recommends a glucose tolerance test before pregnancy or at the first antenatal visit, and a further test at 24 to 28 weeks.
What is metabolic syndrome?
Metabolic syndrome describes the combination of several risk factors: extra belly fat, raised blood pressure, raised triglycerides, low HDL cholesterol and raised blood sugar. A review from 2019 shows that metabolic syndrome is about twice as common in women with PCOS as in other women. Each of these factors increases the risk of heart and blood vessel disease, and together they reinforce each other. More in the article PCOS and the heart.
What about fatty liver?
A fatty liver linked to metabolism (today called MASLD) is more common in PCOS. The main mechanism is insulin resistance: a high insulin level promotes the storage of fat in the liver. A 2023 meta-analysis of 36 studies with about 5,000 women with PCOS found fatty liver in about 40% of women. In the UK Biobank study, about 36% of women with PCOS had a fatty liver on MRI, compared with about 24% of women of the same weight without the syndrome. In both studies, women with raised androgens were affected more.
A fatty liver causes no symptoms for a long time. It can, however, lead to inflammation and scarring of the liver and raises the risk of diabetes. Fatty liver does not affect only the liver. People with MASLD die more often from disease of the heart and blood vessels than from liver disease. A 2021 meta-analysis of 36 studies with about 5.8 million people showed that fatty liver raises the risk of heart attack, stroke and other cardiovascular events by about 45%. When the disease has progressed to fibrosis, the risk is about 2.5 times higher. More about the heart in the article PCOS and the heart.
With a higher weight, insulin resistance or raised liver values, the doctor should therefore also check the liver. How much weight a woman needs to lose for the liver to improve is described in the article PCOS and weight.
Does every form carry the same risk?
The risk of metabolic disorders differs between the forms of the syndrome. Women with raised androgens and an irregular cycle, the so-called classic phenotypes, usually have the highest risk. Women without raised androgens have a lower risk on average, but they still have a risk. Determining the phenotype therefore helps to plan the tests and the treatment correctly for each woman.
How is it treated?
Lifestyle is the basis. A balanced diet and regular exercise improve insulin sensitivity, even without weight loss. With a higher weight, a loss of just 5-10% clearly lowers the risk of diabetes.
Metformin is the best-studied medicine for metabolism in PCOS. The guideline recommends it mainly for women with a higher weight or a higher metabolic risk, on its own or together with the pill. In impaired glucose tolerance, it can slow the progression to diabetes. GLP-1 receptor agonists are a new option for women with a higher weight, together with lifestyle changes and reliable contraception. The latest data on these medicines in the syndrome are described in the article “PCOS and weight”.
The choice of hormonal treatment also takes metabolism into account. Different pills have different effects on blood sugar and blood lipids. In women with a high metabolic risk, the doctor therefore chooses the pill with particular care.
Is the risk lifelong?
Symptoms of the cycle and the skin often become weaker after the menopause. The risk of diabetes, fatty liver and heart disease, however, remains and continues to rise with age. Metabolic follow-up therefore does not end with the wish for a child or with the menopause.
The practice's approach
At the practice, every woman with PCOS receives a complete metabolic assessment, whatever her weight. This includes the glucose tolerance test, blood lipids, blood pressure, waist circumference and, when needed, liver values. The intervals between checks depend on the individual risk.
Treatment combines lifestyle, targeted medication and a careful choice of any hormonal treatment. The goal of the practice is to recognize metabolic disorders early and to prevent diabetes or fatty liver before they develop.
Sources: International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome (Monash University, ESHRE, ASRM, 2023); Teede HJ et al., Human Reproduction 2023. European Society of Endocrinology – The polycystic ovary syndrome: a position statement (Conway G et al., European Journal of Endocrinology 2014). Kakoly NS et al., Ethnicity, obesity and the prevalence of impaired glucose tolerance and type 2 diabetes in PCOS, Human Reproduction Update 2018. Stepto NK et al., Human Reproduction 2013 (insulin resistance in slim women). Lim SS et al., Metabolic syndrome in polycystic ovary syndrome, Obesity Reviews 2019. Henney AE et al., Risk of type 2 diabetes, MASLD and cardiovascular disease in people living with polycystic ovary syndrome, Journal of Clinical Endocrinology and Metabolism 2025. Manzano-Nunez R et al., Non-alcoholic fatty liver disease in patients with polycystic ovary syndrome: a systematic review, meta-analysis, and meta-regression, Journal of Clinical Medicine 2023. Mantovani A et al., Non-alcoholic fatty liver disease and risk of fatal and non-fatal cardiovascular events: an updated systematic review and meta-analysis, The Lancet Gastroenterology & Hepatology 2021.