If you have been told you have PCOS, now called PMOS in Australia, it is understandable to wonder whether insulin resistance is automatic. It is not. Symptoms, body size, a home glucose reading or one fasting-insulin result cannot diagnose it. For assessing glycaemic status, the 75 g oral glucose tolerance test is the most accurate option in current guideline-based PMOS care.
If an oral glucose tolerance test cannot be completed, fasting plasma glucose or HbA1c may be considered, although both are less accurate in PMOS. Routine fasting-insulin and HOMA-IR testing are not recommended because available insulin assays do not provide one reliable cut-off that works across people and laboratories.
Choosing the right test can prevent unnecessary private testing, clarify future diabetes risk, guide pregnancy planning and show whether metformin is relevant to a defined metabolic, cycle or fertility goal.
Quick answers about PCOS, PMOS and insulin resistance
Does everyone with PCOS or PMOS have insulin resistance?
No. Insulin resistance is an important feature of PMOS for many people, but it is not the same condition and is not required for diagnosis. Metabolic risk still needs individual assessment at every body size.
Which blood sugar test is most useful for PMOS?
A 75 g OGTT provides the most accurate assessment of glycaemic status in PMOS regardless of body size. Fasting glucose or HbA1c may be used when it cannot be completed, with lower accuracy. Routine fasting-insulin or HOMA-IR testing is not recommended.
When should you ask a GP about metformin for PMOS?
Ask when impaired glucose regulation, wider metabolic risk, irregular cycles or a selected fertility goal may justify prescription treatment. The reason, dose and review plan are individual. Do not start, stop or change metformin without the prescriber, particularly when pregnancy is planned.
Why does PCOS or PMOS change metabolic risk?
Insulin helps move glucose from the bloodstream into cells. When body tissues respond less effectively, the pancreas may release more insulin to keep glucose within range. Higher insulin can interact with ovarian hormone pathways, increase androgen activity and contribute to irregular follicle development or ovulation.
This mechanism is important, but it does not explain every symptom or establish the diagnosis. PMOS is identified from a pattern of ovulatory, androgen and, where appropriate, ovarian features after other causes are considered. Glucose, insulin, body weight and ultrasound answer different questions.
Australia began transitioning from the name PCOS to PMOS in May 2026. The newer term reflects the condition’s endocrine, metabolic, reproductive and psychological effects. Current records and search results may use either name, and the PCOS to PMOS guide for Australia explains what changed and what did not.
PCOS diagnosis, glucose status and insulin resistance are three different questions
The first question is whether someone has PMOS. That assessment considers ovulatory, androgen and, where appropriate, ovarian features, not an insulin test. The PMOS diagnostic criteria show how cycle history, androgen signs, blood tests, AMH and ultrasound fit together.
The second is whether glucose regulation is currently normal, impaired or in the diabetes range. The oral glucose tolerance test, fasting glucose and HbA1c assess this question with different accuracy.
The third is whether tissues are less responsive to insulin. Insulin resistance is biologically important, but routine clinical insulin assays and calculations such as HOMA-IR are not recommended for everyday PMOS care. A test should be ordered because its result can change management, not simply because it produces another number.
Which PCOS insulin resistance tests are useful in Australia?
This pathway is designed to help you prepare for a GP discussion. It does not diagnose an individual result or replace the pathology reference range.
| Your situation | Useful discussion with your GP | What not to assume |
|---|---|---|
| PMOS is newly diagnosed or no recent metabolic assessment is recorded | Discuss glycaemic testing, blood pressure and a lipid profile. The 75 g OGTT is the most accurate glycaemic test in PMOS. | These tests assess metabolic health. They do not establish the PMOS diagnosis. |
| Fasting glucose or HbA1c is normal, but pregnancy or fertility treatment is planned | Ask whether an OGTT is appropriate because it assesses the response after a standard glucose drink and should be considered before pregnancy or fertility treatment. | A normal fasting result does not provide the same information as an OGTT. |
| A private fasting-insulin or HOMA-IR test is being considered | Ask what decision the result would change and whether guideline-recommended glycaemic testing is already complete. | There is no universal HOMA-IR or fasting-insulin cut-off for every person and laboratory. |
| An OGTT, fasting glucose or HbA1c is outside the expected range | Arrange clinical interpretation and a follow-up plan. The GP may confirm the result, assess other risk factors and discuss treatment or referral. | An abnormal glucose result does not prove that every symptom is caused by PMOS. |
| Current glycaemic testing is normal | Record when follow-up is due. Glycaemic status is generally reassessed every one to three years according to individual diabetes risk. | One normal result is not permanent clearance from future screening. |
Blood pressure is generally checked annually and when pregnancy or fertility treatment is planned. A lipid profile is recommended at diagnosis, with later timing based on the result and wider cardiovascular risk.
Why are fasting insulin, HOMA-IR and glucose monitors not routine PMOS tests?
Fasting insulin measures insulin concentration at one point. HOMA-IR combines fasting insulin and glucose in a calculation. Results can vary with the assay, laboratory method and selected cut-off, which limits their use as universal diagnostic tools.
This does not mean insulin resistance is unimportant. It means the clinically available measurements are not precise enough to carry the whole decision. Current PMOS guidance therefore prioritises glycaemic status and cardiovascular risk factors that have established interpretation pathways.
A home glucose meter or continuous glucose monitor records glucose, not insulin sensitivity. These devices may be useful when recommended for diabetes or another clinical reason, but they do not diagnose PMOS or insulin resistance and do not replace laboratory assessment.
Signs of insulin resistance with PCOS: what can symptoms and history add?
Symptoms can identify a reason to seek assessment, but they cannot confirm insulin resistance. Darkened, velvety skin patches may occur with higher insulin levels. Fatigue, cravings, energy dips, weight changes and difficulty conceiving are less specific and have many possible causes.
Risk assessment also considers previous gestational diabetes, family history of type 2 diabetes, blood pressure, lipid results, medicines, sleep and pregnancy plans. PMOS-related glucose risk occurs across body sizes, so screening should not depend on whether someone appears to fit a particular body type.
Recording cycle changes, androgen-related symptoms, sleep and wellbeing can make a GP consultation more useful. The PMOS symptoms checklist can help organise that history without turning a symptom list into a diagnosis.
What happens after a glucose result?
A normal result means the measured glycaemic markers were within the expected range at that time. It does not certify that insulin sensitivity is perfect, explain every symptom or remove the need for future screening.
A result showing impaired glucose regulation creates an opportunity to discuss sustainable lifestyle support, other cardiovascular risk factors, medicines and the timing of repeat testing. A result in the diabetes range requires clinical confirmation and management using Australian diabetes care pathways.
The result should lead to a documented action. Ask what the finding means, what will change now, when it will be reviewed and whether pregnancy plans alter the timeline.
Lifestyle care without blame or a single PMOS diet
Healthy lifestyle support is recommended for everyone with PMOS, including people whose weight does not change. Goals may include glucose management, cardiovascular fitness, blood pressure, sleep, mood, cycle health and quality of life.
No single diet composition has been shown to be best for every PMOS outcome. A practical Australian pattern can include vegetables and legumes, fruit, mostly wholegrain foods, protein foods, and dairy or suitable alternatives. The Australian PMOS diet guide provides flexible meal-building ideas without promoting severe carbohydrate restriction or a hormone reset.
Movement should be matched to health, pain, fitness, preference and capacity. Sleep, body image, disordered eating and mental health also deserve direct support. Care is more useful when goals are agreed with the person rather than reduced to weight loss alone.
If vitamins or metabolic products are also being considered, the PCOS supplements guide for Australia separates deficiency-led options from products that need extra checking with metformin or pregnancy plans.
What can metformin change in PCOS or PMOS?
Metformin is a prescription medicine that reduces glucose released by the liver and improves the body’s response to insulin. A prescriber may consider it for metabolic outcomes and, in selected situations, irregular cycles or fertility care.
When prescribed specifically for PMOS features, metformin may be used off label in Australia. That does not make the medicine inappropriate. The decision depends on the treatment goal, glycaemic and lipid results, kidney function, other health risks, pregnancy plans, preferences and tolerance. Routine fasting-insulin testing is not required before the decision.
Nausea, diarrhoea, bloating or cramps can occur, particularly when treatment begins or the dose changes. Longer-term use can be associated with lower vitamin B12 in some people, so monitoring may be considered when risk factors or symptoms are present. Ask what benefit is expected, which adverse effects need review and when follow-up is due. Do not use an online dose to start or alter treatment.
Metformin does not cure PMOS, guarantee ovulation or guarantee pregnancy. Inositol can be considered according to individual preferences, but evidence for clinical benefits remains limited and no universal type, ratio or dose is recommended. The inositol evidence guide is the better place to compare those claims.
Where do insulin resistance and metformin fit in fertility care?
When metformin is discussed for fertility, it is only one part of the assessment. Age, semen, fallopian tubes, intercourse timing, ovulation and other reproductive conditions may also affect conception. Improving one blood result cannot answer all of those questions.
When infertility is linked to absent or irregular ovulation and no other infertility factor is found, current guidance recommends letrozole as the first-line prescription medicine to induce ovulation. Metformin may be used in selected cases, but people should be told that more effective ovulation medicines are available. The PMOS fertility and pregnancy pathway places metabolic care within the wider assessment.
When home timing is appropriate, ovulation tests can help identify a urinary LH rise. They do not measure insulin, prove egg release or show whether metformin is working. If cycles are irregular, tracking ovulation with PMOS can help you use a wider testing window and recognise when home results need clinical context.
Metformin, PCOS and pregnancy: what changes when pregnancy is planned?
An OGTT should be considered before pregnancy or fertility treatment when there is no known diabetes. Blood pressure, medicines, supplements and other preconception risks should be reviewed at the same time.
If an OGTT was not completed before conception, it may be offered at the first antenatal visit and again at 24 to 28 weeks. The individual schedule can change because of previous results, gestational diabetes or another clinical risk.
Metformin should not be presented as protection against gestational diabetes, late miscarriage, pregnancy hypertension, pre-eclampsia or high birth weight. Do not stop it simply because pregnancy is possible or confirmed. Ask the prescriber why it was prescribed and what the pregnancy plan should be.
Australian GP checklist for PCOS insulin resistance
Bring
Bring previous glucose, HbA1c, OGTT, insulin and lipid results, recent blood-pressure readings, a medicine and supplement list, cycle information, pregnancy plans and any history of gestational diabetes.
Ask
Ask which test answers the current question, what the result can and cannot show, what would change management, whether metformin has a defined goal, and when screening or medicine review is due.
Leave with
Leave with a test plan, a result-review date, the adverse effects or symptoms that need earlier advice, and a referral threshold. If conception is delayed, cycles are absent or another fertility factor is known, fertility specialist assessment in Australia may be discussed earlier.
Frequently Asked Questions about PCOS, PMOS and insulin resistance in Australia
Can fasting glucose or HbA1c be normal while an OGTT is abnormal?
Yes. Fasting glucose and HbA1c do not measure the response to a glucose drink. In PMOS, an OGTT can identify impaired glucose handling that is not apparent from those tests, which is why it is the most accurate option for glycaemic assessment.
What is the difference between insulin resistance and prediabetes?
Insulin resistance describes reduced tissue responsiveness to insulin and may be present while glucose results remain within range. Prediabetes is a glycaemic classification based on laboratory glucose or HbA1c criteria. They are related, but they are not interchangeable diagnoses.
Does body size decide whether I need glucose testing?
No. Body size can contribute to individual risk, but the PMOS guideline recommends the OGTT as the most accurate glycaemic assessment regardless of BMI. Screening decisions should consider the complete clinical picture and pregnancy plans.
Can metformin be prescribed without measuring fasting insulin?
Yes. A metformin decision can be based on the clinical indication, glycaemic and lipid results, cycle goal, health history and pregnancy plan. Routine fasting-insulin testing is not required by the international PMOS guideline.
What happens if an OGTT is abnormal before pregnancy?
Your GP interprets the result using Australian glucose criteria, may confirm the finding, reviews other risks and develops a treatment and pregnancy plan. Addressing an abnormal result before conception or fertility treatment allows care to be organised earlier.
Does a normal OGTT mean no further PMOS screening is needed?
No. A normal result describes glycaemic status at that time. The usual reassessment interval is one to three years, shortened when health, medicines or pregnancy plans change the risk profile.
Next Steps in Australia
Check whether you have had an OGTT, fasting glucose, HbA1c, lipid profile and blood-pressure review, and note when each was completed. Ask your GP which result is still needed and what management decision it will inform.
If metformin, inositol or fertility treatment is being considered, define the goal before changing the plan. Record how benefit and adverse effects will be reviewed, and do not alter a prescription because of a private insulin score or an online dose.
When pregnancy is the goal, combine metabolic screening with a complete fertility and preconception assessment. Ongoing irregular cycles, an abnormal glucose result or delayed conception should lead to a documented follow-up or referral pathway rather than repeated home testing alone.
Last reviewed: 5 September 2026
Next scheduled review: September 2027
References
Fertility2Family articles are researched using Australian Government health guidance, Australian professional recommendations and peer-reviewed medical literature. These sources support the diagnosis, testing, treatment, fertility and pregnancy boundaries in this article.
Commercial disclosure: Fertility2Family sells ovulation tests. The product-category link appears only where home LH tracking is relevant and does not change the medical evidence, review process or stated limits of ovulation testing.
RANZCOG. RANZCOG Welcomes Polycystic Ovarian Syndrome (PCOS) Renaming to Polyendocrine Metabolic Ovarian Syndrome (PMOS)
Australian professional announcement confirming the May 2026 name change and explaining why PMOS better reflects the condition’s endocrine, metabolic, reproductive and broader health effects.
Human Reproduction. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome
Australian-led international guideline supporting OGTT preference, routine insulin-assay limits, repeat glycaemic screening, lifestyle care, metformin, inositol, fertility treatment and pregnancy recommendations for PCOS.
Medical Journal of Australia. Summary of the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome: an Australian perspective
Australian guideline summary translating evidence on diagnosis, metabolic screening, lifestyle, medicines, fertility and pregnancy into practical implementation considerations for Australian healthcare professionals and consumers.
Healthdirect Australia. Polycystic ovarian syndrome (PCOS)
Australian consumer guidance covering the PCOS to PMOS transition, symptoms, diagnosis, blood sugar and cholesterol testing, treatment, fertility and longer-term metabolic health.
Jean Hailes for Women’s Health. Can PCOS Lead To Other Health Conditions?
Current Australian women’s health guidance describing PMOS-related insulin resistance, glucose intolerance, type 2 diabetes risk, cardiovascular health, sleep and psychological wellbeing without implying inevitability.
Australian Prescriber. Pharmacological management of polycystic ovary syndrome
Peer-reviewed Australian clinical review covering patient-centred medicine selection, metformin’s metabolic and reproductive roles, adverse effects, inositol uncertainty, fertility referral and weight-inclusive care.
Healthdirect Australia. Metformin
Australian consumer medicine information explaining how metformin lowers blood glucose, its use for some PCOS symptoms, common adverse effects and the need for prescriber advice.
Pregnancy, Birth and Baby. Polycystic ovarian syndrome (PCOS) and pregnancy
Australian pregnancy guidance on fertility, preconception care, pregnancy risks and monitoring for people with PCOS, including treatment and support from healthcare professionals.
Healthdirect Australia. Diabetes screening tests
Australian guidance explaining fasting glucose, oral glucose tolerance and HbA1c screening tests, why high-risk people may be tested without symptoms and how laboratory results are used.
Healthdirect Australia. Devices to self-monitor your blood sugar
Australian guidance describing blood glucose meters and continuous glucose monitors for self-monitoring, while distinguishing device readings from laboratory diagnosis and clinician-directed diabetes care.
Australian Government, Eat for Health. The five food groups
Australian healthy-eating guidance covering vegetables and legumes, fruit, mostly wholegrain foods, protein foods, dairy or alternatives, variety and practical balanced meal planning.
Australian Government Department of Health, Disability and Ageing. Recommendations for adults (18 to 64 years)
Current Australian recommendations for daily movement, moderate-to-vigorous activity, muscle strengthening, sedentary time and sleep, supporting flexible plans matched to health, capacity and preference.